to increase strength for moving around in the cabin to keep from becoming overweight on a space mission to minimize the loss of muscle mass due to microgravity to ensure that bodily fluids do not tend to collect in the feet
Which of these is the best reason for exercising on space flights?

Options:
- to increase strength for moving around in the cabin
- to keep from becoming overweight on a space mission
- to minimize the loss of muscle mass due to microgravity
- to ensure that bodily fluids do not tend to collect in the feet

to minimize the loss of muscle mass due to microgravity