Answer:
Killer T cells release enzymes that help destroy invading foreign matter (antigens), Helper T cells, on the other hand, stimulate another type of lymphocyte known as B cells. B cells produce antibody, which is a protein made in response to a specific antigen.
I'm going with C. It may be wrong but I think it's C.
Answer:
The platypus serves as a 'bridge' animal between nonmammals like birds and reptiles, which maintain their testicles in their body cavity, and placental and marsupial mammals, which hold their testes in an external scrotum."
True.
Overlapping food chain is a food web. A food web shows the many different paths plants and animals are connected. eg: A hawk might also eat a mouse, a squirrel, a frog or some other animal.
