Answer:
The correct option is B (natural killer cells).
Explanation:
Natural killer cells: They are defined as the type of cytotoxic lymphocyte which are critical to the innate immune system. The NK cells play an important role in to provide rapid response to tumor formation, virus infected cells, and acting after three days of infection.
While cancer cells die, they release some antigens, than these antigens are recognized by the immune system, and later they are presented on the immune cells which are known as antigen presenting cells. So, if these cells are absent than they increase the chances of developing malignant tumors.
Answer;
C. it is the part f the atom with the greatest mass
Explanation;
The nucleus of an atom is a small dense region at the center of an atom that contains protons and neutrons.
Almost all the mass of an atom is located in the nucleus, with a very small contribution from the electron shells.
The protons are positively charged which gives the nucleus a positive charge while the neutrons have no charge.
B migration, that is the answer
