Answer:
The correct answer is opsonin.
Explanation:
When an antibody or molecule that promotes or increases phagocytosis by marking dead cells for recycling or marking an antigen is called Opsonin. Opsonization is a mechanism in which apoptotic cells or microbes are chemically altered to have a strong drawing ability to the surface receptors of the cell on phagocytes and NK cells.
Opsonization also aids phagocytosis by signal cascades from receptors present on the cell surface. Cell membranes have a negative charge that prevents two cells to come closer but after binding opsonin, it boosts the kinetics of the phagocytosis by interacting with cell receptors That overcome the negative charge of the cell membranes.
Thus, the correct answer is opsonin.