Question

An example of negative feed back loop in humans is

• A. Salivation of mouth at the sight of delicious food.
• B. Constriction of skin blood vessels and contraction of skeletal muscles in cold.
• C. Secretion of tears on dust particles falling in eyes.
• D. Secretion of sweat glands and constriction of skin blood vessels when it is too hot.

Answer 1

The correct option is B Constriction of skin blood vessels and contraction of skeletal muscles in cold.

• Negative feedback is a reaction that causes a decrease in function. It occurs in response to some kind of stimulus. Often it causes the output of a system to be lessened; so, the feedback tends to stabilize the system. This can be referred to as homeostasis. For example, constriction of skin blood vessels and contraction of skeletal muscles in cold.
• So, the correct answer is 'Constriction of skin blood vessels and contraction of skeletal muscles in cold'.