Innate defenses counter specific disease-causing agents, whereas adaptive defenses include mechanical and chemical barriers:

Kidney disease can cause hypertension by activating the renin-angiotensin mechanism.
This mechanism involves the release of renin from the kidneys, which stimulates the production of angiotensin II, a hormone that constricts blood vessels and increases blood pressure.
Choice A is wrong because kidney disease does not directly signal the brain stem to increase blood pressure.
The brain stem regulates blood pressure through the autonomic nervous system, which responds to various stimuli such as stress, pain, or emotions.
Choice C is wrong because kidney disease does not increase the release (excretion) of sodium and water.
On the contrary, kidney disease can impair the ability of the kidneys to filter out excess sodium and water, which can lead to fluid retention and increased blood pressure.
Choice D is wrong because kidney disease does not stimulate the secretion of ANP.
ANP stands for atrial natriuretic peptide, a hormone that is secreted by the heart when it senses high blood pressure.
ANP causes the kidneys to excrete more sodium and water, which lowers blood pressure.

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.