In the mammal, the autonomic system consists of

Explanation

The question is asking about the autonomic system in mammals. The autonomic system is responsible for controlling involuntary actions in the body such as heart rate, breathing, and digestion. The options given are: sympathetic and parasympathetic systems, brain and spinal nerves, brain and cranial nerves, and spinal cord and spinal nerves. The correct answer is option A, which states that the autonomic system in mammals consists of sympathetic and parasympathetic systems. The sympathetic system is responsible for the fight or flight response, which prepares the body for action in response to stress or danger. The parasympathetic system, on the other hand, is responsible for the rest and digest response, which helps the body to relax and recover after a stressful event. It is important to note that the autonomic system is part of the peripheral nervous system, which is responsible for transmitting information between the central nervous system (brain and spinal cord) and the rest of the body. The brain and cranial nerves and spinal cord and spinal nerves mentioned in the other options are also part of the peripheral nervous system, but they are not specifically related to the autonomic system. In summary, the correct answer to the question is option A, which states that the autonomic system in mammals consists of sympathetic and parasympathetic systems.