Which of the following statements about positive feedback mechanisms is not true?
a. positive feedback mechanisms can result from human activity.
b. positive feedback mechanisms can occur naturally.
c. positive feedback mechanisms lead to increased change.
d. positive feedback mechanisms reduce change in a system

The correct answer is d  the positive feed back reduces change in the the system

Explanation:

In an  biochemical reaction when the released product stimulate the release and activation of the same product and act together to exibit their biological function, then this type of regulation is called positive feedback.

     The positive feed back mechanism leads to increased change in the system that"s why it is named so.

    For example during blood clotting platelets molecules are released to form clots to stop bleeding. one activated platelet can stimulates the activity of other platelets which then join together to form a group for generating further blood clots.

d. Positive feedback mechanisms reduce change in a system

Explanation: :)

a time line cause it goes from 685 to 978

1. amino acid refers to the fundamental building block of proteins, comprising of an amino group and a carboxyl group.

2. catalyst refers to any substance, which increases the rate of chemical reaction without being used up in the reaction.

3. a complex molecule containing he genetic code is dna or deoxyribonucleic acid.

4. an enzyme refers to a molecule of protein, which is unique in accelerating up a particular chemical reaction in the biological systems.

5. nucleic acid refers to an sequence of sugars, phosphates, and nitrogenous bases, for example, dna and rna.

6. a protein refers to a large, composite organic molecule comprising of a huge number of amino acids associated together with the of peptide bonds.

7. rna refers to a nucleic acid that takes part in the production of proteins.

8. substrate refers to a compound, which takes part in a chemical reaction, and is chemically modified by the reaction.