Give three reasons why the polar ice caps do not support any vegetation

Answer:

descent with modification

Explanation:

Answer: Simple microscope

Anton van Leeuwenhoek in 1679 developed a simple microscope. He observed first living single celled organism under microscope. He observed pond water, soil-water mixture, a drop of hay infusion under microscope and found single celled living organisms like protozoa, bacteria.

Answer: Endosymbiosis

Explanation:

During the 1980s a theory was proposed to explain the origin of chloroplast and mitochondria from the permanent resident prokaryotes.

according to this theory, large prokaryotes engulfed smaller prokaryotes, instead of digesting the smaller one both entered into a type of relationship known as mutualism where both organism were benefited.

The larger prokaryotes gained more energy which provided protomitochondrion and excessive sugar lead to the formation of chloroplast.

The goal of applying maximum parsimony when constructing phylogenetic trees is to create a tree that represents evolutionary relationships with the fewest number of events, reflecting the simplest possible explanation.

To apply parsimony to constructing a phylogenetic tree, scientists adopt the maximum parsimony principle, which suggests that the phylogeny with the least number of evolutionary events, or the simplest explanation, is the most likely. The principle assumes that nature does not operate in a complex and convoluted manner when a simpler alternative exists. This concept, similar to Ockham's razor, is grounded in the idea that the simplest hypothesis that explains the data should be selected. Maximum parsimony is often contrasted with maximum likelihood, another principle suggesting that the most likely sequence of evolutionary events is the one that probably occurred. An analogous example of maximum parsimony is when a group of people enters a forest preserve to hike, and one could predict that most would hike on established trails rather than forging new ones.

The autonomic nervous system controls the body's unconscious actions, split between the 'fight or flight' sympathetic system and the 'rest and digest' parasympathetic system.

The autonomic nervous system primarily controls the body's unconscious actions. These are the mechanisms in the body that we don't actively think about but are vital for survival. The autonomic nervous system is divided into two main groups: the sympathetic and parasympathetic systems. The sympathetic system prepares the body for 'fight or flight' situations, increasing heart rate and blood flow to muscles, for example. In contrast, the parasympathetic system promotes 'rest and digest' activities, slowing the heart rate and promoting digestion.

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The autonomic nervous system directly controls internal organs, smooth muscles, and glands. It operates outside of conscious control and is divided into the sympathetic and parasympathetic nervous systems, which work together to maintain balance, or homeostasis, in the body.

The autonomic nervous system most directly controls the internal organs, such as the lungs and heart, as well as smooth muscle, and exocrine and endocrine glands. It operates largely without conscious control, continuously monitoring conditions and implementing changes as necessary. The autonomic nervous system is divided into two subsystems that often have opposite effects: the sympathetic nervous system and the parasympathetic nervous system.

The sympathetic nervous system prepares the body for stress-related activities while the parasympathetic system returns the body to normal, routine operations. These two divisions work in tandem to maintain the body's homeostasis.

For instance, the heart receives connections from both the sympathetic and parasympathetic divisions. One causes the heart rate to increase (sympathetic), whereas the other causes the heart rate to decrease (parasympathetic). This dual influence helps maintain a balance in heart function.

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The selective pressure comes from a) the environment.

In artificial selection, humans provide the selective pressure for species to change and shape the evolution of various breeds.

The environment includes all the natural factors that influence an organism's survival and reproduction. These factors could be:

Predators - For example, animals that can avoid being eaten by predators are more likely to survive and reproduce.

Food Availability - Organisms that are more efficient at finding or using food sources have a better chance of thriving.

Climate - Organisms that can tolerate extreme temperatures or other climate-related factors will do better in their habitats.

Mating Preferences - Traits that are found attractive by potential mates can also become more common over generations.

These environmental pressures ensure that individuals with advantageous traits are more likely to survive and reproduce. Over many generations, these advantageous traits become more common within the population, leading to evolution. This process is gradual and happens naturally without human intervention.

A codon is a sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid or stop signal during protein synthesis.

Amino acids play central roles both as building blocks of proteins and as intermediates in metabolism.

The genetic code is traditionally represented as an RNA codon table because, when proteins are made in a cell by ribosomes, it is mRNA that directs protein synthesis. The mRNA sequence is determined by the sequence of genomic DNA. With the rise of computational biology and genomics, most genes are now discovered at the DNA level, so a DNA codon table is becoming increasingly useful

The branch of science which deals with the study of gradual change of species is called evolution.

The correct answer is species.

These are the eras in which the major species which dominates the land and the earth were reptiles.

During those eras, the reptiles are the common link.

Hence, the correct answer is reptiles.

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Latitude is the angular expanse of the north or south of the equator of the earth, while longitude is the angular distance of a place east or west of the meridian at Greenwich, England, or object. The latitude and longitude of the following cities are:

A.      Kansas City - 39.0997⁰ N, 94.5786⁰ W

B.      Philadelphia – 39.9526⁰ N, 75.1652⁰ W

C.      Reno – 39.5296⁰ N, 119.8138⁰ W

D.      Minneapolis – 44.9778⁰ N, 93.2650⁰ W

The latitude and longitude (to the nearest degree) of the following cities are: Kansas City – 39.0997⁰ N, 94.5786⁰ W, Philadelphia – 39.9526⁰ N, 75.1652⁰ W, Reno – 39.5296⁰ N, 119.8138⁰ W, and Minneapolis – 44.9778⁰ N, 93.2650⁰ W.

A spherical or geodetic coordinate system known as the geographic coordinate system is used to measure and transmit positions on Earth as latitude and longitude.

In spatial reference systems, the most basic, traditional, and often utilized. It also serves as the foundation for the majority of other systems.

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A decongestant like phenylephrine functions by binding to the adrenergic receptors in the bronchioles of the lungs and stimulating dilation. This process helps clear mucus accumulated in the respiratory tract, effectively opening the nasal passages and alleviating congestion.

A decongestant's primary action in opening nasal passages revolves around its effect on the adrenergic receptors in the bronchioles of the lungs. For instance, phenylephrine, a common component of decongestants and a sympathomimetic drug, acts as an α₁-adrenergic agonist. This means it binds to specific adrenergic receptors, stimulating a physiological response.

Upon binding to these receptors, phenylephrine causes the bronchioles to dilate or widen. The widening of the bronchioles allows for the clearing of accumulated mucus in the lower respiratory tract, thereby reducing nasal congestion. This mechanism is typically active in drugs like Tylenol Sinus or Excedrin Sinus where phenylephrine is paired with other pharmaceuticals like analgesics.

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Differences in normal values for hemoglobin and red blood cell counts in males and females are due to physiological differences between the genders. These differences can lead to conditions like anemia, when these levels are deficient, or polycythemia, when there's an overproduction of red blood cells.

Hemoglobin levels and red blood cell counts have different normal values in males and females due to physiological differences between genders. Hemoglobin is a molecule present in erythrocytes (red blood cells) that carries oxygen, and a deficiency in its number or in the number of RBCs can result in a condition called anemia.

The volume of erythrocytes (also known as the packed cell volume or PCV) tends to differ in males and females. In normal conditions, erythrocytes make up about 45 percent of a blood sample. For females, hematocrit ranges from 37 to 47 percent and for males, hematocrit ranges from 42 to 52 percent. The gender-dependent difference in these hematocrit values accounts for the different normal values for RBC counts and hemoglobin levels in males and females.

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