Group 13-17 contains metalloids. Boron, Silicon germanium, Arsenic, Antimony, Tellurium and Polonium are considered metalloids. They have properties of both metal and non metal. Some of the element are good semi-conductors .
"Natural selection<span> is the differential survival and reproduction of individuals due to differences in </span>phenotype<span>. It is a key mechanism of </span>evolution<span>, it is a change of </span>heritable traits<span> in a </span>population<span> over time"</span>
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.
