Earth scientists often use to represent complex objects or processes.

model

Explanation:

When a scientist is against a very complex idea, one of the steps that the scientist takes is simplify (for example, hey may suppose that during the process the temperature is constant, or things like that) as much as him/her can. The objective here is creating a model from where he can start to predict the behavior of the object or the processes, and then with scientific analysis and experimentation the scientist can, first probe or refute his/her model, and if the model seems to work, with the further investigation this model can be perfectioned.

The complete sentence is:

Earth scientists often use a model to represent complex objects or processes.

renewable resources- resources that can be replenished (such as trees)

nonrenewable resources- resources that are gone once they are used (such as fossil fuels)

producer-person who makes goods or provides services

consumer- person whose wants are satisfied by using goods and services

allocate- distribute

choice- option

(hope this ! )