Both. You can use it as singular or plural.
Answer:
The hemocytoblast (option B) are the parent cell for all formed elements of blood
Explanation:
All blood cells are originated from a common stem cell, which is called a pluripotent stem cell. It is capable of giving rise to any of the blood cells maintaining its existence through mitosis. By dividing pluripotent stem cells, new cells are originated, which become multipotent and differentiate into lymphoid (NK cell and the polymorphonuclear cell) or myeloid cells (megakaryocite); always respecting the original quantity.
The correct option is D. This is because, mucus, inflammation and fever perform different functions in the immune system.The mucus membrane produces mucus which traps microbes. Inflammation refers to a localized tissue response which occurs when a tissue is damaged. Fever inhibits bacterial growth and speed up the rate of healing of a damaged tissue.
