Please help!

What are the exchange pools for Carbon?

Carbon pool

Earth's carbon pools.

The ocean (~37,000 GtC).

Terrestrial ecosystems (~3,000 GtC).

Earth's crust (sedimentary rocks ~75,000,000 GtC).

The atmosphere (~830 GtC).

3 hours because it is a decent distance.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.