The number of species on Earth tagged at 8.7 million as of 2011.
Answer;
-Cell division
Explanation;
-Glandular epithelium forms the covering of all major glands. It is also present in the intestinal lining.
-Cells are regenerated by division in the basal layer and migrate toward the apical surface to replace cells lost by fragmentation. Cell division is indicated by the mitotic phase cells located in the deepest (basal) layer of the glandular epithelium.
The *heart* is the main organ of the circulatory system.
The circulatory system consists of three independent systems that work together: the heart (cardiovascular), lungs (pulmonary), and arteries, veins, coronary and portal vessels (systemic). The system is responsible for the flow of blood, nutrients, oxygen and other gases, and as well as hormones to and from cells.
