Final answer:
To keep astronauts healthy and able to exercise in space, doctors must ensure that the astronauts' cells receive the necessary nutrients from food and air. Regular exercise with specially designed equipment and a nutrient-rich diet are crucial to counteract the effects of microgravity on muscle and bone density.
Step-by-step explanation:
To ensure astronauts' bodies work well enough to exercise in space, doctors must ensure astronauts' cells are getting the molecules they need from food and air (option c). This is essential because, in the microgravity conditions of space, significant changes occur in how body systems function. As there is no gravity to pull blood and bodily fluids down toward the legs, fluids redistribute toward the head, which can affect the astronaut's health. To counter the negative effects of weightlessness, such as muscle and bone loss, astronauts need to perform regular exercises using specially designed equipment that simulates resistance.
Astronauts experience rapid bone mass loss due to the lack of gravitational forces. This can lead to a condition similar to osteoporosis on Earth. Providing astronauts with a nutrient-rich diet that's high in calcium and vitamin D, along with resistance and weight-bearing exercises, can help alleviate this condition. Moreover, ensuring proper sleep, hydration, and protection against the increased radiation levels in space are also critical for maintaining long-term astronaut health. Therefore, constant monitoring and a personalized healthcare plan are crucial for the well-being of astronauts in space.