Mutations that occur without a known cause are known as:
a. spontaneous mutations
b. induced mutations
c. harmful mutations
d. adaptive mutations
e. reversion mutations

a. spontaneous mutations

Explanation:

Spontaneous mutations occur randomly in all cells and without any agents. Induced mutations are the result of some exposure to a physical or chemical agent called a mutagen. Mutations can be classified as harmful and adaptive regardless of whether they were spontaneous or induced mutations. The reversal mutation is when a given mutation is reversed by another mutation so that the nucleotide is changed back to its original state.

true is the

the wetland preservation movement began in the u.s. in earnest with the clean water act (cwa) of 1972. although not specifically written to protect wetlands, the cwa is comprised of a series of regulations designed to prevent pollutants from contaminating u.s. waters.