Constitutes about 80% of circulating antibodies in plasma.
a. igg
b. ige
c. iga
d. igm

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

•there must be variation for the particular trait within a population.

•the variation must be inheritable (that is, it must be capable of being passed on from the parents to their offspring).

•individuals with one version of the trait must produce more offspring than those with a different version of the trait.good

explanation:

b a mature ovary of a plant.