When a variation outside normal limits triggers a response that restores the normal condition, the regulatory mechanism

(a) negative feedback.
(b) positive feedback.
(c) compensation.
(d) adaptation.

(a) negative feedback.

Explanation:

A negative feedback mechanism operates in the direction of maintaining the homeostasis. Any change from the defined range of internal conditions of the body is sensed as a stimulus. It triggers a response that restores the original range of the internal condition. This is called a negative feedback mechanism. For example, when the body temperature rises, the blood vessels present near the skin surface dilate to lose more heat to the environment. This is one of the negative feedback produced against raised body temperature.

answer: after carbon dioxide enters the leaf through stomata it moves into the mesophyll cells where photosynthesis occurs and glucose is constructed. respiration occurs when glucose (sugar produced during photosynthesis) combines with oxygen to produce useable cellular energy.

explanation:

the sun's light combined with the visible wavelenghts form what is called ultraviolet radiation, which are the long waves at the end of a visible light sprectrum.

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