"according to nasa, astronauts experience a 1% loss of bone per month in space. under microgravity conditions, osteoblast activity decreases and osteoclast activity increases ."

based on this information, which of the following explains the risks an astronaut might experience after a long mission in space?

a - bone stress would cause bone tissue to thicken
b- bone erosion would cause hormonal secretion's that decrease the absorption of calcium.
c- bone destroying cells would outnumber bone-building cells causing thinning
d- bone absorption would cause the matrix to lack calcium