Mechanical stress applied to bone increases osteoblast activity in bone tissue, and the removal of mechanical stress decreases osteoblast activity.
Explanation:
Osteoblasts are cells , that are produced in the bone marrow and are responsible for formation of bones and bone matrix.
Whenever a mechanical stress is applied on the bones , a series of reactions are triggered. As a result the activities of osteoblast increases to synthesize more and more bone matrix to provide strength.
Again on the other hand a decrease in mechanical causes a decrease in the activities of the osteoblasts.
Thought and action are the two main functions
The answer is C: <span>The Neanderthals cared for the wounded and the elderly. The fact that the skeleton showed signs of broken bones that had healed indicated that the individual had been nurtured back to health after injury. The loss of teeth showed that the individual had lived to an old age.</span>
<span>Perhaps surprisingly, lakes and rivers constitute a tiny proportion of the world's total freshwater, so answer (b) is correct. Most of the freshwater on our planet is in fact locked up in ice and glaciers, some 68%. The majority of the rest, 30%, is actually underground, in springs and other groundwater feeders. That leaves just 2% that makes up all the rivers, lakes, ponds and other visible freshwater reservoirs that we see in our day-to-day lives.</span>
