Every cell of the organism has the same DNA sequence and same genes. However, not all genes are expressed in every single cell at the same time. Only those genes necessary for a specialised function of a specialised cell are expressed in the specialised cell. For example, skin cells have some different proteins than nerve cells. Genes responsible for those "skin proteins" are activated in skin cells and are turned off in nerve cells.
<u>Answer</u>:
The high sea surface salinity can be observed in the Pacific Ocean, the Indian Ocean, the Arabic ocean and the Mediterranean sea.
<u>Explanation</u>:
Due to rainfall and evaporation of water from sea the density varies with varying salts and minerals concentration that aggregate at the surface. The salinity in the seawater varies according to the amount of evaporation from a particular area.
Low salinity water is found in polar and subpolar regions that are near to the equator. Regions of high salinity are observed in the seawater which is centered around 30 degrees north and 30 degrees south to the equator due to the excess evaporation in these areas.
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.
Answer:
the answer is B
Explanation:
because pangaea was a super continent
