Directional selection can be distinguished from disruptive selection by a. the elimination of extreme variations of traits
b. selection for two extreme variations of a trait
the preservation of gene frequencies
d. selection for one extreme variation of a trait

CORRECT ANSWER IS D

Which best describes the nucleus of an atom a. it is where all of the particle s of the atom are located b. it is the negatively charged part of the atom c. it is where the electrons and the protons are located d. it is the part of the atom with the greatest mass

Imagine a self-reactive t cell that has not undergone clonal deletion in the thymus (that is to say, it has escaped central tolerance). if it encounters self antigen in the absence of an infection or inflammation, what will happen to this self-reactive t cell? (select two answers) (a) the t cell undergoes clonal expansion. (b) the t cell gains effector functions. (c) the t cell undergoes apoptosis. (d) the t cell becomes activated. (e) the t cell becomes anergic.

Explain how the parts of the peripheral nervous system work with the central nervous system to produce a response to the stimulus