Define continuous cropping

Continuous cropping is the growing of a single crop species on a field year after year. It's the act of progressive planting, and allows soil fertility to recover.

I hope this helps! :)

i believe the correct answer from the choices listed above is the first option. the scientists need to look at the   validity of data, claims, hypotheses, and observations before  developing an argument. they base their arguments on facts that are present and they make sure they have proofs. 

explanation:

digestion

it excretes wastes