What is a b cell
a.)a pathogen that makes antigens
b.)a lymphocyte that makes antibodies
c.)an antigen that makes antibodies
d.)a virus that makes bacteria

B.)A lymphocyte that makes antibodies

Explanation:

B cells creates antibodies, which help fight foreign viruses and bacteria to help prevent an individual from getting sick.

the correct answer is:

a population changes in response to a change in the environment.

some fungi obtain their nutrients from a living host (plant or animal) and are called most biotrophic fungi have fairly narrow host ranges—they are specialized on a limited called rhizomorphs that allow the fungus to grow from one tree to another. ascospores are formed inside a sac-like structure called an ascus. so your answer is a