AP BIOLOGY

Detailed explanation-1: -A callus presents as a broad-based diffuse area of hard growth with relatively even thickness, usually at the ball of the foot. It lacks a distinct border. The affected skin is rough and discoloured, varying in colour from white to gray-yellow or brown. Calluses are more common in women than in men.

Detailed explanation-2: -Callus is defined as a group of cells derived from competent source tissue that is cultured under in vitro conditions to form an undifferentiated mass of cells.

Detailed explanation-3: -Callus is a growing mass of unorganized plant parenchyma cells. It is mainly used in plant tissue culture. So basically in other words, callus is a undifferentiated mass of tissue.

Detailed explanation-4: -The two basic types of calluses are the discrete nucleated and the diffuse-shearing.