Polygenic inheritance. The characteristics of a person aren't controlled completely by a single gene, but rather several genes that generally only make a small contribution to how the child turns out in the outcome. At one point there was a study that showed over 400 genes were linked to height, so imagine any other characteristics of a person. Environmental effects also serve a large purpose in how a child is to turn out. These children may all be growing up in the same environment, however that's not to say they all grow up the same. They could all be treated the same way and react differently to it, this counts both for physical and mental traits. All human's features such as eye colors, hair color and height are determined by several different genes. As an example, there are around 2 major eye color genes, however there are also around 14 different genes that actually contribute in determining a person's exact eye color. Some are bound to look the same, as they have the same parents, however, just because they have the same parents doesn't mean they all will look exactly alike.
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Explanation:
There are many options, here are a few choices:
Fast moving water tends to be colder than slow water; some of it originates as snow melt on the sides of mountains, for example. For this, animals in fast water tend to be more cold resistant. This is why you do not see fish like freshwater trout in equatorial regions. These animals struggle and die in slow, warm water.
Fast moving water means that if the animal or plant wants to stay put, it must resist the flow. Fish tend to be far more muscular and lean in these places, while insects like stoneflies, mayflies, and other larvae have ways to secure themselves to rocks and plants while growing. Plants develop strong root systems, and algae hold fast in rocky crevices in the river. Some animals also have suction in order to stay in place where there is fast flowing water.
Some animals have to adapt their reproductive systems as well. Because finding a mate is difficult in the sweeping waters, breeding tends to happen all at one time. As an example, salmon have runs, where thousands of fish all swim upriver at once to breed, can dramatically alter the surrounding ecology of the river. Insects like mayflies have hatches, where hundreds of thousands of flies swarm into the air at once to breed and lay eggs.
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D
Explanation:
because the sun is energy
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3. the absence of a cell wall in human cells
Explanation:
Animal cells do not have cell walls. Cell membranes separate the cytoplasm of the animal cells from the surroundings and maintain their interior. Plant cells have cellulosic cell walls. A cell wall surrounds the cell membrane of a plant cell. Cell walls serve to provide structural support and protect plant cells from pathogens. Cell walls also help keep excess water out of cells so they do not burst. Therefore, human cheek cells would not have cell walls while the onion cells would have cell walls made up of cellulose.
