Answer:
Vacuum
Explanation:
A vacuum is usually defined as a space in which there is an absence of matter. It can also be said that there is an extremely low amount of pressure due to which the particles present in it are not affected by any type of process that occurs in space. The value of pressure is lower than the value of normal atmospheric pressure.
For example, sound cannot travel in space because there is no medium such as water and air through which the sound waves can propagate.
There is much more fresh water underground than on the surface. A rock layer must be porous and permeable to be a good aquifer. An impermeable layer makes up the bottom of an aquifer. The water table rises and falls with additions or subtractions to the groundwater system.
Answer:
interleukin-2 (IL-2) is an interleukin, a type of cytokine signaling molecule in the immune system. It is a 15.5–16 kDa protein[5] that regulates the activities of white blood cells (leukocytes, often lymphocytes) that are responsible for immunity. IL-2 is part of the body's natural response to microbial infection, and in discriminating between foreign ("non-self") and "self". IL-2 mediates its effects by binding to IL-2 receptors, which are expressed by lymphocytes. The major sources of IL-2 are activated CD4+ T cells and activated CD8+ T cells
Explanation:
genetic drift
Explanation:
Genetic drift is changes in allele frequencies of a gene pool due to chance or random events. This can occur in large or small populations. Genetic drift causes gene pools of two isolated populations to become dissimilar as some alleles are lost and other are fixed.
