The original amount of po-239 was 5725 g, How much would be remaining after 4 half lives

How does natural selection change thephenotypes within a population over time?

Which type of transport is responsible for oxygen entering into blood cells? a. vesicle b. passive c. facilitated d. active b. passive

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.