Explanation:
HIV attacks a specific type of immune system cell in the body. It's known as the CD4 helper cell or T cell. When HIV destroys this cell, it becomes harder for the body to fight off other infections. When HIV is left untreated, even a minor infection such as a cold can be much more severe.
Answer:
(1)
Explanation:
there are different divisions of the spinal cord but as a whole there are 31 segments
Answer:
phospholipids, sterols, and triglycerides
Explanation:
Phospholipids make up the outermost layer of cells in the bodies of both animals and humans. They create a protective layer around the cells to help maintain them.
Sterols are a subset of steroids, a type of hormone.
Triglycerides are the fats and oils that you are familiar with in foods. This type of lipid can be saturated or unsaturated, which is part of what makes them solid or liquid, respectively, at room temperature.
The Cambrian explosion was a period at the Pre-Cambrian boundary of the geologic time scale at 542 Ma. At this boundary, the fossil record shows that animals suddenly appeared in a dramatic radiation of life. A radiation is the relatively rapid development of new types of organisms that derive from a common ancestor. The Cambrian explosion is important because it marks the origination of all major animal groups called phyla.
Because the majority of cell differentiation occurs during the EMBRYONIC phase, .................. The embryonic stage of pregnancy is the period after implantation during which all the important organs and structures in the growing fetus is formed. Tetratogens are factors that caused malformation of embryo. Exposure to tetratogens during embryonic stage cause most destructive damages.
