Which of the following types of cells can directly kill cells and secretes a chemical known as perforin which accomplishes the killing by producing pore-like openings in the membranes of cells?
a. cytotoxic t cells
b. t cells
c. antibodies
d. natural killer cells

Cytotoxic T cells

Explanation:

Perforin is the cytosolic protein and upon degranulation forms pores in the target cell. Perforin protein helps in the transport of water and ions.

Perforin is present in the granules of cytotoxic T cells. These cells have the ability to kill virus infected cells and cancer cells. Cytotoxic T cells bind with the class 1 MHC molecules. These cells are also known as CD8+ T cells.

Thus, the correct answer is option (A).

weathering is the answer.

did you fail the test? xd