A secondary immune response occurs when an antigen is encountered on a second occasion, due to exposure to a pathogen that previously caused infection. Which property of some viruses explains the lack of a secondary immune response

Viruses could have a high mutation rate

Explanation:

Viruses replicate very fast when they enter into the bloodstream. This isn’t however the real cause of why a secondary immune system isn’t possible against them.

The main cause is because they mutate rapidly. The immune system already has an idea of the genetic composition of the pathogen exposed to previously and knows how to fight it. But the viruses undergoes some genetic alterations which then makes it hard for the secondary immune response to attack and kill them.

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.