Science is based on "natural" causes and effects. What does "natural" mean in this context?
O Phenomena that can be reliably observed with senses or instruments; NOT
supernatural.
O Phenomena that occur on their own without being manipulated; NOT
controlled.
O Phenomena that occur without the direct participation of humans; NOT
artificial.

○Phenomena that occur on their own without being manipulated;Not controlled.

Explanation:

the word natural means which already existed in nature and not controlled by anyone or a thing, where the Phenomena that occur on their own without being manipulated; Not controlled.

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.