Final answer:
The Medulla contains the cardiac center, which is responsible for controlling the cardiovascular system through autonomic connections and maintaining homeostasis.
Step-by-step explanation:
The structure that contains the cardiac center is the Medulla. The medulla is part of the brain stem, which also includes the midbrain and pons. The cardiac center is responsible for controlling the smooth and cardiac muscle of the cardiovascular system through autonomic connections. This center ensures the homeostasis of the cardiovascular system is maintained, especially during changes such as fluctuations in blood pressure.
It achieves this through the coordination of the autonomic system. Furthermore, when descending inputs from the hypothalamus stimulate this area, the sympathetic system can increase activity in the cardiovascular system in response to conditions like anxiety or stress. The correct answer to the question 'Which structure contains the cardiac center?' is A) Medulla.