Final answer:
A space suit helps an astronaut by providing the necessary pressure to simulate Earth's gravity, aiding in blood circulation and preventing muscle and bone loss in the absence of gravity.
Step-by-step explanation:
The suit forces blood to certain parts of the body to counteract the absence of gravity. In the microgravity environment of space, such as aboard the International Space Station, the absence of a significant gravitational force can lead to blood pooling in the upper body. This can have negative effects on the cardiovascular system, as on Earth gravity helps to maintain a pressure differential Hath is higher at the feet than at the head. The space suit provides pressure to simulate this differential, aiding in the circulation of blood throughout the body and helping to prevent muscle atrophy and bone mass loss that can occur due to weightlessness.
Additionally, while space suits do have systems in place for regulating gas exchange and monitoring oxygen levels, these are not directly related to how pressure assists the body's function in space, as suggested in other answer choices. Space suits maintain a balanced internal environment, providing pressurization necessary for the lungs to function properly in the vacuum of space, similar to how atmospheric pressure on Earth allows for oxygen and carbon dioxide exchange during breathing.