USE RACES: Why is a food web a better model for explaining energy flow
than a food chain?

Explanation:

Because it shows the relation of organisms with each other in a habitat, rather than just a small segment of it like a food chain. It is also still pretty easy to understand like a food chain.

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.