A newborn is protected against certain digestive and respiratory infections by IgA received via the mother:

It explains that the primary immune response produces antibodies within five to ten days of exposure to antigens, while the secondary immune response produces antibodies within a day or two of subsequent exposure to the same antigen.
This is because the primary immune response involves the activation and differentiation of naive B cells into plasma cells and memory cells, while the secondary immune response involves the rapid activation of memory cells into plasma cells.
Choice A is wrong because the primary and secondary immune responses can occur in both children and adults.
Choice B is wrong because the primary immune response is slower than the secondary immune response in producing antibodies.
Choice D is wrong because both primary and secondary immune responses are important for the body’s ability to protect itself from pathogens.
The primary immune response generates immunological memory, while the secondary immune response provides a faster and stronger response to repeated infections.

Circulation is the movement or flow of something, especially blood or air, through a circuit or a specific course.
Circulation supplies oxygen and nutrients to and removes wastes from tissues. This is essential for the survival and functioning of cells and organs.
Choice A is wrong because circulation does not inflate the lungs.
The lungs are inflated by the pressure difference between the air inside and outside the chest cavity.
Choice C is wrong because circulation does not deliver waste to tissues.
Circulation removes wastes from tissues and delivers them to the excretory organs such as the kidneys and the lungs.
Choice D is wrong because circulation does not deliver carbon dioxide to tissues and removes excess oxygen.
Circulation does the opposite: it delivers oxygen to tissues and removes carbon dioxide.
Carbon dioxide is a waste product of cellular respiration that needs to be eliminated from the body.