Which of the following statements is true? all mutations cause evolution. natural selection favors organisms which are well adapted to the environment. genetic drift is the only way to add new genes to the gene pool of a population. horseshoe crabs have almost identical structures to fossils from 250 million years ago. this is an example of speciation.

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.