HORTICULTURE

Detailed explanation-1: -The correct option is B tropism. The movement of a whole plant or a part of plant, in response to the direction of stimulus is called tropism. The stimulus can be water, sunlight or gravity. Different parts of plants respond to the same stimuli differently.

Detailed explanation-2: -In biology, a tropism is a phenomenon indicating growth or turning movement of an organism, usually a plant, in response to an environmental stimulus. In tropisms, this response is dependent on the direction of the stimulus (as opposed to nastic movements which are non-directional responses).

Detailed explanation-3: -Phototropism is the directional growth of an organism in response to light. Growth toward light, or positive tropism is demonstrated in many vascular plant, such as angiosperms, gymnosperms, and ferns. Stems in these plants exhibit positive phototropism and grow in the direction of a light source.

Detailed explanation-4: -Gravitropism (also known as geotropism) is a coordinated process of differential growth by a plant in response to gravity pulling on it. It also occurs in fungi.

Detailed explanation-5: -The movement or growth of any part of a plant in response to an external stimulus is called tropism or tropic movement.