Q1.
the young stages of frogs are called tadpoles. the tadpoles live in fresh water.
the drawings show a tadpole just before hatching and three days after hatching.
structure x in the exchange of substances between the tadpole and the water.
structure x
tadpole just
before hatching
tadpole three days
after hatching
(a)
name one substance, other than food, that the tadpole needs to exchange with the
water in order to grow.

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.