Answer:
b
Explanation:
The pulmonary circulation is a division of the circulatory system in all vertebrates. The circuit begins with deoxygenated blood returned from the body to the right atrium of the heart where it is pumped out from the right ventricle to the lungs.
Answer:
A population of rattlesnake in the state of Florida.
Explanation:
A population refers to the group of individuals of a species present together in a defined region at the same time. All the members of a particular population belong the same species and hence, are able to interbreed to produce fertile progeny. Since they belong to same species, individuals of a population also share several common morphological traits.
Some of the attributes of a population are natality (the birth rate), mortality (the death rate), density (number of individuals per unit area), sex ratio, etc.
Therefore, the given example explains the population of the rattlesnake in the state of Florida.
Answer:
Vaccine
Explanation:
I'm not sure but it seems like the most logical answer.
It is intended to increase immunity against that antigen back to protective levels, after memory against that antigen has declined through time.