The practitioner examines his client's foot and observes the great toe to be black and dry. the practitioner explains to the client that the dead tissue is caused by:

dry gangrene

Explanation:

Gangrene is not a special form of necrosis, it is a particular form of evolution of a necrosis, which is conditioned by certain germs. These germs act on proteins, especially on hemoglobin, and decomposition products give the blackish color characteristic of gangrene. Pathogenetically there are two different forms of gangrene: ischemic and infectious.

Ischemic gangrene

It occurs in the underlying skin and soft tissues, most often in the lower extremities due to atherosclerotic obstruction. Necrosis is caused by ischemia and saprophytic germs on the skin act secondarily on the necrotic tissue. Depending on the conditions of the compromised tissue, dry or wet ischemic gangrene occurs.

Dry gangrene In this way the evaporation of water quickly produces a drying of the compromised skin, which transforms into a blackened, dry brown, corrugated sheet. The compromised territory is well demarcated, the germs do not penetrate the depth, there is no intoxication of the organism.

the answer would be d