Arteries are distinguished from veins based on all of the following features except a the direction of blood flow relative to the heart. b the amount of oxygen present in the blood. c the structure of their walls. d the blood pressure. e All of the choices are correct.

The response is the basis for vaccination. primary secondary tertiary none of the above

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.

In a village where the proportion of individuals who are susceptible to malaria is .70 and population is at hardy-weinberg equilibrium what population is heterozygous hba/hbs