Which layers of sedimentary rock at grand staircase escalante national monument
do you think are the oldest?

What kind of bond is created by the attraction between atomic particles of opposite charge? ionic bond hydrogen bond covalent bond nuclear bond

Natural selection changes allele frequencies because some survive and reproduce more successfully than others.

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.