UNIVERSE
LIFE IN THE SOLAR SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The lack of certain nutrients in their food
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Swallowing their toothpaste
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Weightlessness in microgravity
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The absence of a magnetic field
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Detailed explanation-1: -Bone loss occurs in the weightless environment of space because bones no longer have to support the body against gravity. On Earth, gravity applies a constant mechanical load to the skeletal system, that causes healthy bones to maintain a certain density so that they are able to support the body.
Detailed explanation-2: -A microgravity environment causes a cephalic fluid shift that effectively pumps more blood to the upper region of the body and less blood to the legs (Blaber et al. 2010). This explains the pattern of major bone loss in the legs.
Detailed explanation-3: -Microgravity has the opposite effect. It reduces the load that gravity naturally places on muscles, interrupting protein synthesis so that fibers begin to atrophy. This loss of muscle mass contributes to reduced skeletal muscle strength when astronauts return to Earth.
Detailed explanation-4: -Without the proper diet and exercise routine, astronauts also lose muscle mass in microgravity faster than they would on Earth. Moreover, the fluids in the body shift upward to the head in microgravity, which may put pressure on the eyes and cause vision problems.