Answer: Natural selection is one of the forces of evolution and the enviroment where the species lives is the selection agent. For example, suppose a mosquitoes population in a environment free from insecticides, in this environment there's a high frequency of non-resistant mosquitoes because the environment is not exerting any pressure on the resistence trait. But when the environment changes and we use a insecticide upon the mosquitoes population, the populations changes because the non-resistant ones die but those resistant survive and beggin to reproduce more effectively. That's natural selection, differences in survival and reproduction between individuals with different phenotypes (traits) and this differences depend of environmental changes.
Answer:
Regions of ER that lack bound ribosomes are called smooth endoplasmic reticulum, or smooth ER.
Answer and Explanation:
When a cell is freezed, it cytoplasm-which is mostly water- is frozen and its volume expands. In consequence, pressure inside the cell increases and that causes damage to the outer wall.
The same occur in an unopened softdrink when it freezes. The volume inside the container increases and the pressure increases. If this volume increment is not considered before freezing the liquid, it could cause the container damage or breaking.
Answer:
Megaloblastic anemia is most often due to hypovitaminosis, specifically vitamin B12 (cobalamin) and folate deficiencies, which are necessary for the synthesis of DNA. [3] Copper deficiency and adverse drug reactions (due to drug interference with DNA synthesis) are other well-known causes of megaloblastic anemia.
Explanation:
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Answer:
When the seed germinates, the two cotyledons emerge from the soil to form the seed leaves. The seed leaves nourish the plant until it can form its true leaves. (Not all dicots' seed leaves emerge during germination; for example, peas are dicots, but the pea cotyledons remain underground.)
Explanation: