Cytotoxic t (tc) cells are like a natural killer (nk) cell because they both
a. secrete interferons.
b. secrete granzymes and perforin.
c. participate in the immune response.
d. participate in nonspecific resistance.

B. secrete granzymes and perforin.

Explanation:

Perforins are the proteins that perforate the plasma membrane of the target cell and lead to bursting of cells due to holes formed in its membrane. Granzymes are the proteolytic enzymes. They serve to stimulate the target cells to kill themselves by the process of apoptosis.

Binding of natural killer cells to their target cells stimulate the release of granules that are filled with perforins or granzymes to kill the target cells.

Likewise, cytotoxic T cells bind to the infected body cells and release the granules filled with perforins or granzymes to kill those infected cells.

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.