What effects occur to the bones of astronauts who spend a prolonged period in space? what effects occur to the bones of astronauts who spend a prolonged period in space? weight-bearing exercises are minimal due to the weightlessness of space, leading to the decreased amount of compression and tension on bones and decreased osteoblast activity. osteoblast activity is stimulated due to the weightlessness of space and the astronaut will continually remodel his bones to account for the weightlessness. weightlessness will strengthen the muscles and increase bone mass while stimulating osteoblast activity. weight-bearing exercises are easier due to the weightlessness of space, leading to the increased amount of compression and tension on bone and increased osteoblast activity.

The best answer to the question: What effects occur to the bones of astronauts who spend a prolonged period in space? Would be: Weight-bearing exercises are minimal due to the weightlessness of space, leading to the decreased amount of compression and tension on bones and decreased osteoblast activity.

Explanation:

The process of bone formation, bone mass maintenance, and reformation, depends on the play of different factors, but most importantly, on the availability and need of the body for calcium, and the activity of two cells: osteoblast and osteoclasts, who are constantly remodeling bone. Most importantly of all regarding astronauts are osteoblasts, whose job is to reform bone, while osteoclasts break it apart to release calcium. Due to the exposure to prolongued atmospheres of zero gravity (space), these osteoblasts do not perform their task as they should and astronauts may loose as much as 20% of their bone mass due to these conditions of zero gravity, within a few days. To counter this, science developed exercises, especially with weights, to help diminish this effect of lack of gravity on bone. However, as of 2012, despite these exercise programs, astronauts, especially those in long voyages, were still presenting problems. This is why new exercise programs were developed to add resistance exercises to weightlifting, to encourage osteoblasts to resume their proper function of bone formation. And this is why the best answer is the first statement.

Weight-bearing exercises are minimal due to the weightlessness of space, leading to the decreased amount of compression and tension on bones and decreased osteoblast activity.

Explanation:

lifetime activities are certain actions that are either required throughout your life or you choose to do them. for example, eating is considered a lifetime activity, drinking water or other beverages, keeping your body clean, taking medicine. those types of actions are considered lifetime activities.

answer: c more big rigs and commercial vehicles

explanation: because big rigs drive far to deliver products overnight