When an enemy cell is present, a(n) secretes perforins, which bore a hole in the enemy cell membrane. a. interleukin
b. antibody
c. interferon
d. natural killer cell
e. opsonization

The correct answers is D. Natural killer cell

Explanation:

Natural killer cells are a type of cell in the immune system. These differ from other cells because these are innate, this means they attack all enemy cells or pathogens and are not specific. Also, they are the first general immune defense.

Moreover, the role of these cells to attack any enemy cell including cancer cells is possible due to specific chemicals or substances these cells release. One of these is perforins, which are mainly released by natural killer cells and destroy these by creating lesions in the cell membrane. According to this, the correct answer is D.

there are mainly three domains in biological classification namely; archaea, bacteria, and eukarya.

archaea includes all the prokaryotic cells which are characterized by their lipid membranes. they have branched hydrocarbon which is attached to glycerol through an ether linkage.

bacteria includes all the prokaryotic cells, the cell membrane of which are made up of the unbranched fatty acid chain. in addition, they are attached to glycerol through an ester bond.

eukarya includes all the eukaryotic cells, that is, the cells contain a nucleus and other membrane-bound cell organelles.

they can be autotrophic as well as heterotrophic, unicellular as well as multicellular

they include kingdoms like protista, plantae, animalia, fungi et cetera.

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