This is because the GP120 protein
of the HIV virus that forms the ‘knob’ is
essential for the infection of CD4 cells
of the immune system by the virus. The glycoprotein is, therefore, a good
target for vaccines especially since the
molecule is highly conserved because most mutations in the region could be highly deleterious to the virus.
Answer: C) mixture
Explanation:
A mixture can be define as a combination of two or more substances in which the identity of each substances is retained. In a salad lettuce, tomatoes and onions are separate entities which are combined to form a mixture that is salad.
Placental mammal is the answer.
Answer:
C.
Explanation:
Here, surface area is the area of the outside of the cell, called the plasma membrane. The volume is how much space is inside the cell. The ratio is the surface area divided by the volume. This indicates how much surface area is available compared to how big the cell is.