The answer is C. My answer is because A and B are irrelevant to the question, so for that it can be eliminated. But between C and D, C makes much sense. Although D, says that seals are warm blooded and is true, however frogs (amphibians) and snakes (reptiles) they are cold blooded. They need sun in order to feel warm or the heat to adjust or accommodate their bodies temperatures, unlike panthers and seals they’re warm blooded they naturally have fur and are able to regulate their bodies temperature. Therefore D is eliminated. The correct answer is C, because seals have fur and blubber it’s much more durable, and are almost as if impenetrable for the freezing water and colder weather to pass through their fur. That is why they are able to live the coast of Antarctica.
Plasma cells are designed to churn out Antibodies. These are proteins that have a variable region which is complementary ( perfect shape fit) for the virus' antigen and can therefore bind to the antigen, making the virus harmless or tagging it to be consumed by a phagocyte.
Low levels of estrogen is a sign that the ovaries of a woman are beginning to fail. This is a common occurrence when one is at menopausal stage. Estrogen and progesterone naturally decrease and eventually stops the menstrual cycle. Hope this helped.