The major organ of the circulatory system that causes blood to flow through the body by its pumping action is the heart.
Answer:
A
Explanation:
If there are more predators than prey, the ecosystem will fall and the predators will die of starvation or cannibalism
The jugular veins are the veins responsible for bringing deoxygenated blood from the head to the heart. There are two sets of jugular veins, the internal and external ones. In pigs, the internal and external jugular veins are similar in size, while in humans the internal jugular vein is bigger in diameter than the external.
B. an ecosystem
An ecosystem contains a community (several species of organisms) and the environment including air, water, and more.
