Which resource is sometimes unpredictable in terms of production?

sorry to break it to ya but no one can answer your question it's just

jk but i am serious about the part that most people cant answer it beacuse you did not mention the section you are talking about. but it would if you added some detail and were a bit more specific.

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.

dna is a set of a gene held together by a chemical bond