I would say immigration only.
emigration would theoretically reduce the genetic variation as unique individuals leave, but immigration would bring unique traits into circulation in an ecosystem.
I'm not super great at biogy tho so this might not be right... :)
Birds, insects, and many reptiles excrete nitrogenous waste in the form of uric acid, which saves water.
Nitrogenous waste in the body tend to form toxic ammonia, which must be excreted. Mammals such as human excrete urea, while birds, reptiles, and some terrestrial invertebrates produce uric acid as waste in the form of a white paste or power. The production of uric acid involves a complex metabolic pathway that is energetically costly in comparison to processing of other nitrogenous wastes such as urea or ammonia, it has the advantages of reducing water loss and, hence, reducing the need for water.
<span>This result is produced by the selective permeability of the plasma membrane when the presence of negatively charged ions does not diffuse into the cell and the action of several sodium-potassium pump units causes an unequal distribution of charges through the membrane.</span>
T<span>his reaction, known as nuclear fusion, converts hydrogen atoms into helium. The by-product of nuclear fusion in the </span>Sun's<span> core is a massive volume of </span>energy<span> that gets released and radiates outward toward the surface of the </span>Sun<span> and then into the solar system beyond it.</span>
The answer is; cancer occurs due to unregulated cell division
This causes them to proliferate causing a mass of cells and affect neighboring tissues. The cells are usually undifferentiated and therefore do not function properly as tissue. This unregulated division is due to malfunction of the tumor suppressor gene that is significant in cell cycle regulation and apoptosis.
