Crossing over during meiosis creates recombinant chromatids with new combinations of genes and increases genetic diversity in gametes. This results in a high potential for genetic variation in the offspring produced through sexual reproduction.
Explanation:Crossing over is a critical mechanism in genetics that contributes to genetic variation in sexually reproducing organisms. This process occurs during prophase I of meiosis, where homologous chromosomes pair up and exchange genetic material, creating new combinations of genes. Here are two key ways that crossing over contributes to genetic variation:
Creation of recombinant chromatids: A single crossover event between homologous non-sister chromatids results in the reciprocal exchange of equivalent DNA segments. This exchange mixes the genetic material contributed by the maternal and paternal chromosomes, leading to new combinations of alleles on each chromatid.Increased diversity in gametes: Since crossing over can happen at various positions along the chromosomes, different gametes produced by meiosis will carry different combinations of maternal and paternal genes. This leads to a vast number of possible genetic combinations when gametes fuse during fertilization, contributing significantly to the genetic diversity of offspring.These mechanisms, along with independent assortment and random fertilization, ensure that each individual produced through sexual reproduction has a unique genetic makeup. For example, in humans, this can result in more than 64 trillion genetically unique potential combinations from just one couple.
Which of the following can be used by scientists to date the sediment layer they are found in? Select all that apply.
radioactive isotopes
fossils
tree rings
animal growth rings
mineral elements
need answers ASAP please!!
Radioactive isotopes & fossils can be used by scientists to date the sediment layer they are found in
Explanation:
Carbon dating is one of the methods used to determine the age of rocks. Because C-14 has a half-life of 5,730 years by determining the amount of C-14 remaining in the rocks layer in relation to nitorgen-14, the stable element that it decays into.
The fossils embedded in the sediment layers can also be used to determine the relative age of the sediment layers. Older fossils are found are usually found in the lower layers of sediments while younger fossil are found in the upper layers of sediments.
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Final answer:
Radioactive isotopes, fossils, and tree rings are all valid methods for dating sediment layers. Radioactive isotopes are used in radiometric dating, fossils provide relative dating data, and tree rings offer precise dating through dendrochronology.
Explanation:
In the dating of sediment layers, multiple methods can be applied, each using different processes to indicate the age of materials. Among these, radioactive isotopes are key in a method known as radiometric dating, which can date igneous and metamorphic rocks and is also applicable to sediments containing organic material. Fossils themselves can provide relative dating information by their placement within rock layers; the deeper the fossil, the older it is presumed to be.
Dendrochronology, or tree rings dating, is another method used by scientists. This relies on the annual growth rings of trees to determine the age of sediments especially when the wood is found associated with those sediments. Animal growth rings, such as those found in mollusk shells or fish otoliths, can also provide data for dating sediment layers.
The presence of certain mineral elements may help to date a sediment layer, but it does not involve radioactive dating or organic processes, and therefore is less reliable than the aforementioned methods for precise dating purposes. Hence, radiometric dating using radioactive isotopes and dating through association with tree rings or fossils are particularly useful for dating sediment layers.
Question 4 of 10
2 Points
A trait is influenced by several genes. There are two alleles for each gene.
What is the best classification for the inheritance pattern of this trait?
O
A. It is determined by polygenetic inheritance,
O
O
B. It is determined by homozygous recessive alleles.
O
C. It is determined by incomplete dominance.
O
D. It is determined by multiple alleles for each gene.
SUBMIT
Answer:
It is determined by polygenetic inheritance (NB I think this should read polygenic inheritance)
Explanation:
Polygenic inheritance occurs when multiple genes act together to produce one trait. A good example of this in humans is height. The trait for height is not simple the result of 2 alleles of 1 gene, but 2 (or more) alleles of several genes that all work together to determine height. These traits are sometimes called complex traits or quantitative traits and do not undergo simple Mendelian inheritance.
A trait influenced by several genes with two alleles each is characterized by polygenetic inheritance. This is a system where multiple genes cooperate to express a trait, allowing for a wide range of phenotypes.
Explanation:A trait that is influenced by several genes and has two alleles for each gene is best classified as being determined by polygenetic inheritance. In this model, multiple genes, or polygenes, cooperate to express a particular trait. For example, human height and skin color are both determined by polygenetic inheritance. Unlike single-gene inheritance patterns such as homozygous recessive alleles or incomplete dominance, polygenetic traits can exhibit a wide range of phenotypes because they depend on a larger number of genetic variables.
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Copper exists in nature as two isotopes. The atomic masses and relative abundance of these isotopes is given in the table. What is the average
atomic mass of copper?
Isotope
Cu-63
Cu-65
Relative Abundance(%)
69.17
30.83
Atomic Mass (am)
62.93
64.94
A. 62.93 amu
B. 63 55 amu
C. 63.935 amu
D. 64.94 amu
E. 127.87 amu
The average atomic mass of the copper from the two given copper isotopes is 63.55
Explanation:
The average atomic masses of the isotopes of an element is calculated by the addition of the masses of the two isotopes in proportionality to their percentage of natural occurrence.
Cu-63 relative abundance 69.17 Atomic mass 62.93
Cu-65 relative abundance 30.83 Atomic mass 64.94
Average atomic mass= Cu 63 Atomic mass*relative occurrence percentage+ Cu 65 Atomic mass*relative occurrence percentage
62.93*0.692+64.94*0.308
= 63.546 amu is the average atomic mass of copper.
Question 18(Multiple Choice Worth 3 points)
(04.03 HC)
Synthetic compounds that mimic the biological function of the sex hormone estrogen have been found in the marine environment. How would this pollutant be
classified, and why is this a public health concer?
It is a pathogen. It might disrupt growth and development in marine organisms.
It is an environmental pollutant. It might disrupt sexual reproduction in marine organisms.
It is a genetic factor. It might be toxic to marine organisms and lead to death, changing the population structure.
It is both a pathogen and an environmental pollutant. It might lead to food shortages.
Answer:
It is an environmental pollutant. It might disrupt sexual reproduction in marine organisms.
Explanation:
It is a pathogen. It might disrupt growth and development in marine organisms. - false. Estrogen and similar synthetic compounds cannot be classified as a pathogen. Pathogens are microorganisms that cause disease. Estrogen is a hormone, not a pathogen.
It is an environmental pollutant. It might disrupt sexual reproduction in marine organisms. - true. In this case, synthetic chemicals that mimic estrogen function have leaked into the environment, meaning it is an environmental pollutant. Because estrogen is a sex hormone that exists in all vertebrates (not just humans), its artificial existence in the environment will cause effects in marine life when exposed to it. This could interfere with sexual reproduction.
It is a genetic factor. It might be toxic to marine organisms and lead to death, changing the population structure - false. Although esrtogen can impact gene expression, it will not be considered a genetic factor. It would also unlikely be toxic to marine life, as they also possess estrogen.
It is both a pathogen and an environmental pollutant. It might lead to food shortages - false. Estrogen cannot be classified as a pathogen.
A. What gases were present in Earth's early atmosphere?
Answer:
The early atmosphere was probably mostly carbon dioxide, with little or no oxygen. There were smaller proportions of water vapour, ammonia and methane. As the Earth cooled down, most of the water vapour condensed and formed the oceans.
Explanation:
The gases that were present in Earth's early atmosphere are methane, ammonia, water vapour, and the noble gas neon,
What were Earth's early atmosphere?An atmosphere was primarily generated by gasses ejected by volcanoes when Earth cooled. It contained methane, hydrogen sulfide, and ten to 200 times the amount of carbon dioxide found in the atmosphere today. The Earth's surface cooled and cemented enough after roughly 500 million years for water to accumulate on it.Their research was initially focused on bodies the size of asteroids, but because methane was so prominent, they decided to expand their findings to Earth.
They came to the conclusion that the gas combinations utilized in the Miller–Urey synthesis of organic molecules, such as CH4, H2, H2O, N2, and NH3, were present in the early Earth's atmosphere.
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s-waves cannot travel through liquids,including earths?
Answer:
Shear waves cannot travel in liquids or gases -- so, for example, S waves don't travel through the ocean or through the outer core. Surface waves are called surface waves because they are trapped near the Earth's surface, rather than traveling through the ``body'' of the earth like P and S waves.
when an atom gains or loses electrons , the charged particle that results is called a(n)
Answer: Ion / Ions
Explanation: When a neutral atoms loses or gains electrons they become charged atoms in which called as ions.
Compare and contrast the structure and function of the plasma membrane to the structure and function of the cell wall.
well usually cell wall helps to maintain the shape of the plant cell which plasma can't do.
both of them controls movement of substances into in and out of the cell.
sturuture:plasma membrane contain outer membrane that surrounds the entire contents of cell and made of protein and phospholids.
cell wall are strong n rigid, made from celllouse fibre and fully permeable
Answer: The plasma membrane is made up of a two lipid layer which contains transport proteins and other carbohydrates. The plasma membrane is a living layer and selectively permits materials to go in and out of the cell. Micro molecules such as water and oxygen gas diffuses in the lipid layer while macro molecules such as glucose and amino acids enters through the help of transport proteins: channel and carrier proteins.
For the cell wall it is made up of cellulose which makes it hard and rigid. The cell wall is a nonliving layer. It supports the cell and gives strength as well.
Explanation:
A completed Punnett square shows all of the following except
Answer:
A completed Punnett square shows all of the following except "the actual results of a genetic cross"
Explanation:
As we know, that genetic crossing is the determined breeding of the two specific individuals which results in the mixing of the genetic materials that are visible in the offspring. These crosses can be done in the different models like plants, yeasts, flies and also in the mice. These organisms are mostly used for the dissection to know the genetic processes or can be used for creating some novel characteristics. They are mostly two types i.e. monohybrid and dihybrid cross.
A Punnett Square shows all combinations of genes an offspring might inherit from two parents, but it does not show the offspring's actual physical appearance or observable traits (the phenotype), or detail the mechanisms of gene action.
Explanation:A Punnett Square is a tool used in genetics to determine the possible genotypes of offspring resulting from a cross between two individuals, each having a particular genotype. It visually displays all possible combinations of alleles transmitted by each parent to the offspring, allowing the prediction of the probability of offspring inheriting a given genotype.
However, it's important to note that there is one major thing a Punnett square does not show: the actual physical appearance or observable traits (the phenotype) of the offspring. Although the genotypes are represented, the phenotype may not be determined by a Punnett square alone because dominance, co-dominance, incomplete dominance, and other genetic effects are not depicted by this tool. Also, it does not detail the mechanisms of gene action or how certain genes may interact with each other or the environment to express a phenotype.
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A scientist wants to observe the structure that joins a cell to neighboring
cells. How should the scientist observe the detailed structure of the cell?
) A. The scientist should prepare a culture of the cell.
O
B. The scientist should prepare a medium for the cell.
O
c. The scientist should use a light microscope.
D. The scientist should use an electron microscope.
Cells are the smallest, functional, and structural living beings. The cell is composed of different organelles and carries out vital functions. If a scientist wants to observe the cellular structure, then they should use a microscope.
The correct answer is:
Option D. The scientist should use an electron microscope.
Cells are microscopic living entities, which can be observed through a microscope. The features of an electron microscope are:
1. Electron Microscope have a much shorter wavelength than visible light, which helps in the better resolution of the specimen.
2. The microscope uses a beam of accelerated electrons to power the source of illumination.
3. Electron microscope is widely used to observe biopsy samples, metals, cells, and macromolecules.
Thus, the electron microscope will be used by the scientist to observe a clear and magnified structure of the cell.
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Answer:
D:Scientist should use an electronic micromicroscope
Explanation:
According to the law of conservation of matter, matter is never created or destroyed. Yet in a food pyramid the amount of
biomass decreases as we move up through the pyramid, from producers to top level consumers. Why?
In a food pyramid the amount of biomass decreases as we move up through the pyramid, from producers to top level consumers because, Matter changes to other forms that might not continue to be a part of the same food chain.
Explanation:
It is essential for any living organism to maintain a good health for survival. The good health refer in attaining the necessary nutrients. This can be achieved using the Food pyramid. This helps in getting the nutrients at accurate amount that is helpful in maintaining a good health. There are similar types of nutrients that exists in a food type. These are classified under one group and they form the food pyramid.
Producers are those that have ability to make food for them on their own. For example plants. Plants can get carbon dioxide from atmosphere prepares food for them through photosynthesis process and releases oxygen that helps humans to survive. Consumers are those that depends on something for their food. In a food pyramid, when we move upwards, as the matter changes its forms, which will not sometime become a part of similar food chain, there will be a decrease in the biomass amount.
A chimp has 24 chromosomes in each of her body cells. How many chromosomes
would be in each of her eggs?
What is purpose of our life as humans evolved from million years of evolution...What is your view of your life....Why we have a consciousness?...What is consciousness anyway?
Answer:
The main purpose of everything that exist world is to create more suitable and better environment for future.
Explanation:
As humans are the most developed species in the globe because they have the power to evaluate and conceive the activities going on in the surrounding.The most valuable thing we humans have is the consciousness i.e. we know how things work and can modify it.By using this awareness ability we have been in the race of evolution through millions of years making our environment more advanced and better.Do the shortest duration of insolation and the minimum temperature occur in the same month?
Answer:
Yes, the shortest duration of insolation and the minimum temperature occur in the same month.
Explanation:
The shortest duration of insolation occurs in month of December and sometime the minimum temperature may also occur in the month. The shortest day of the year is December 21 and insolation at that day is also shortest of the year. If the sun is out for a longer time the temperature will be much greater, because the sun is shining for a greater amount of time.Structures in plant leaves that open and close to maintain homeostasis are called _____.
flowers
stomata
stems
nodes
Answer:
stomata
Explanation:
Stomata are "pores" located on the underside of leaves to let out water and maintain homeostasis (internal balance) within the plant.
Which of these is an example of land contamination?
O
A. Desertification
* O
B. Garbage dump
O
C. Recycling bin
O
D. Deforestation
Answer:
B
Explanation:
desertification and deforestation are effect of land contamination and other environmental threats.
this is a recycle bin...and it wont harm anyone...It will recycle the grabage and...help our environment.
Garbage dump will contaminate our water ways with hazardous chemicals...and it will release green house gases like methane....and also when enough methane was produced it can even cause explosions...dont foget the bad odour.
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An example of land contamination is garbage dumps. The correct option is B. Garbage pollutes the land, water, and air.
What is contamination?Contamination is the state or presence of unwanted and undesirable things or elements that pollute, infect, or make dirty a place. Contamination can be of anything, and it affects both the place and the health of the people.
Garbage is the unwanted or filthy elements that have to dispose of carefully, but garbage dumping anywhere contaminates the land, water, and air.
Thus, option B. Garbage dump is correct regarding contamination of land.
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Which rocks are examples of chemical sedimentary rock? Check all that apply.
coal
iron ore
rock salt
limestone
sandstone
Answer:
Rock Salt (Halite), Limestone, Iron ore
Explanation:
Sandstone is a clastic sedimentary rock
Coal is an organic sedimentary rock.
Limestone, rock salt, and some types of coal are examples of chemical sedimentary rock. Iron ore and sandstone are not considered chemical sedimentary rocks.
Explanation:Chemical sedimentary rocks are formed by precipitation of minerals from water. Precipitation can be caused by several geological processes. A large amount of these rocks are composed of mineral salts and include examples such as limestone, rock salt, and even some types of coal.
However, iron ore and sandstone are not classified as chemical sedimentary rocks; they fall under different categories. Iron ore is formed from a chemical reaction, but it is generally classified as a mineral instead of a rock. Sandstone, on the other hand, is an example of a clastic sedimentary rock, not a chemical one.
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Which phase occurs directly after s phase
Full question:
Which phase occurs directly after s phase...
A. G1
B.G2
C. Cytokinesis
D.M phase
The phase that occurs directly after s phase is G2 phase.
Explanation:
The Synthesis phase is termed as S phase. This phase in the cell cycle occurs between two phases namely G1 and G2.It is the place where the replication of DNA takes place. This phase will make the DNA to chromosome and this is highly regulated. This phase is an important phase in the cell cycle as the replication of DNA occurs in this phase.
Apart from the replication of chromosomes, the growth of the cell that starts in the G1 phase will be continued with this phase. Thus when the replication of DNA is full done, then S phase will be completed and it proceeds to the G2 phase.
Kyle does an experiment to test the effectiveness of a new type of fertilizer. He predicts that the fertilizer will make plants grow twice as fast as they would without the fertilizer.
After the experiment is complete, Kyle's collected data show that the fertilizer only worked 60% of the time. Kyle decides to remove the data that contradicts his prediction from his published results so that his published conclusion will show that the fertilizer is 100% effective.
The published results of Kyle's experiment
A.
are invalid because experiments cannot be done on plants.
B.
are valid because the fertilizer was over 50% effective.
C.
are valid because scientists should always throw out contradictory data.
D.
are invalid because they are based on incomplete data.
Answer:
The correct option is D) are invalid because they are based on incomplete data.
Explanation:
A scientist should always show the complete data of results for his research. It is unethical for a researcher to show incomplete data and frame his results based on the incomplete data do that his work gets published. Results based on incomplete data cannot be considered to be valid in scientific research. Manipulation of data is unethical and should never be done in scientific researches. Hence, option D is correct.
Answer:
C
Explanation:
tissue structure experiment please.
Answer:
Histology is the branch of biology which is related to the study of tissues.
The following are the general steps which are to be taken to examine a tissue under a microscope.
Fixation:Fixation protects the tissue from autolysis. It hardens the tissue due to which it becomes easier in cutting the thin sections of a tissue. Fixation is done with the help of chemicals like aldehydes.
Selection:Selection is done to isolate the particular tissue which we want to observe.
WaxingParaffin waxing is done so that the tissue remains embedded.
Staining:Staining is done so that the tissue can be seen and separated from other tissues.
MicroscopeThe tissue can then be observed under a microscope.
how does nitrogen leave a food chain?
A. Primary consumers eat nitrogen-containing green plants.
B. Producers absorb nitrogen-containing nutrients by their roots.
C. Decomposers break down nitrogen-containing waste material from primary consumers.
D. Denitrifying bacteria convert nitrogen-containing nutrients in the soil into atmospheric nitrogen.
Answer: c
Explanation: Plants and animals need nitrogen to make proteins but they cannot take it in from the air. Because nitrogen is unreactive as a gas, it has to be transformed into a new molecule. When bacteria in the soil takes nitrogen from the air, it becomes nitrates. Finally, it can move through the food chain in this form.
What would most likely be included in the "Analysis" section of a lab report?
Complete Question:
What would most likely be included in the “Analysis” section of a lab report?
1) a discussion of any errors in the experimental data
2) a list the supplies that were used in conducting the experiment
3) suggestions for new experiments based on the results
4) a description of what the dependent and independent variables were
Answer:
1). a discussion of any errors in the experimental data.
In the analysis section of the lab report, after analyzing and investigating the data, errors are identified in the experimental data. Furthermore, discussion carried out to point out those error occurred in the data. In an analysis process discussion is carried out to find the errors in the whole process. In this process all facts and figure are gather to inquire if there are any errors or mistake present in the final values or final result. Analysis section in a lab report has a key role because it make sure that the final result is error free.
A farmer found that one tree in his pear orchard bore especially delicious fruit. Which method would most quickly provide a large crop of these pears?
Answer:
Grafting branches from this tree onto other trees in the orchard.
Explanation:
In the field of gardening, grafting can be described as a procedure in which a part of a plant such as the shoots with desirable traits is cut in an inclined manner and joined to the another plant's parts such as the roots or shoots. As a result, the two plants are united and they will grow. Such a technique will allow other crops to also produce delicious fruit. Hence, grafting is an effective technique used by farmers to produce more plants with favourable characteristics.
If nitrates are not assimilated into plants, what else could happen to them?
Answer:
Nitrate assimilation is a process through which nitrogen is acquired in green algae.The macro elements of nitrogen is the most essential and abundant component for living matter for growth and development and productivity.
Explanation:
If nitrates are not assimilated into plants then the green algae or Chloro phyte algae that require nitrogen which will be obtaining from nitrate will not enter into their body and as the result of this, their growth and development hampers and also it also decreases their productivity.
Who pioneered the use of galvanoplastic compounds for preserving footprints and ballistics?
OA Mathieu Orfila
B. Calvin Goddard
C. Edmon Locard
D. Alphonse Bertillon
E. Dr. Joseph Bell
Reset
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B. Calvin Goddard pioneered the use of galvanoplastic compounds for preserving footprints and ballistics.
Explanation:The pioneer in the use of galvanoplastic compounds for preserving footprints and ballistics is B. Calvin Goddard. Goddard, an American forensic scientist, developed a method called bullet identification or ballistics fingerprinting, which involved analyzing the unique markings left on bullets and cartridge cases. He made significant contributions to the field of forensic science and his work on ballistic identification revolutionized criminal investigations.
explain some of the various medieval literary forms. why were writers employing these literary forms?
Answer:
Medieval poetry, medieval drama, medieval allegory, medieval mysticism, medieval travel literature are some forms of medieval literature. The writers employed these forms to expand the boundaries of literature disciplines.
Explanation:
The discipline of literature can be referred to as the most ancient of all knowledge disciplines. It is because the art of literature existed, humans could grow through understanding. The medieval literature was rich in content and spoke mostly about contemporary ideals, values, lifestyles, thoughts, etc.. Why are the effects of acidic deposition often felt in ar-
eas far from where the primary pollutants are produced?
Answer:
Acid desposition is very harmful for the environment because it can easily combine with primary pollutants like carbon monoxide, particulate matter, sulfur oxide etc and form harmful substances.
Explanation:
Acid desposition means acid forming pollutants in the atmosphere that can easily combines with the primary pollutants which is emitted from car and energy power plants.One of the major culprit is sulful dioxide which is released from car. Once they react with water, produce sulfuric acid and nitric acid. Their pH is extremely low thus they acts as acid.These acidic desposition create hazards in aquatic body,wetlands,aquatic fishes,shell fishes,may cause nitrogen pollution and also cause damage in ecosystem.This is the main reason that acidic desposition often felt in area far from pollutants so that it does't hamper the ecosystem.Explain the relationship between ocean circulation patterns and the marine food chain, and how
this is affected by an El Nino event,
Answer:
Ocean circulation patterns is directly linked with the marine ecosystem. El Nino event hinders the climate interaction of ocean.
Explanation:
The disturbance in the ocean climate interaction transfers the essential nutrients into the deep down ocean leaving very tiny amount at the surface. It lacks the support to plankton growth.Ocean circulation patterns can sometime make the ocean food ecosystem less productive.El Nino event reverses the ocean current. Surface waters in the central and eastern Pacific Ocean become significantly warmer than usual during this event. So the drifting starts towards east direction (normally driven west).Antibiotics do not work against what
Answer:
antiboitics don't work against viruses as it has no " target " to viruses
Explanation:
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An organism dies, and its body leaves an
impression in mud. Over time, the mud
hardens into rock, and the impression
becomes a fossil. Which kind of fossil was
formed? SC.7.L.15.1
Answer:
sedimentary rock fossil and if am not correct am sorry I tried
Answer:
mold
Explanation:
because it changes over time and formes to a formation of mud