Answer:
the cylindrical bundle of nerve fibers and associated tissue which is enclosed in the spine and connects nearly all parts of the body to the brain, with which it forms the central nervous system.
Answer:
excretion is the action of expelling waste from one's body.
Explanation:
<u>Answer</u>: C) Directional selection occurs when one of two extreme phenotypes is selected for.
The type of natural selection known as directional selection is defined in population genetics in the case in which an extreme phenotype is favored over other phenotype. Thus, the population and its allele frequency will evolve towards this end of the trait spectrum (extreme phenotype). This is also the case illustrated in the graph where the right side represents the extreme phenotype.
I think the answer is nitrogen fixation.