Which type of relationship do the parrotfish and the rabbitfish have in the corral-reef environment

The answer is Commensalism. This is a kind of symbiotic relationships, it is an association of organism benefits the others while the other is unharmed. Also it is a relationship between two organisms where the one benefits the other while the other is not affected.

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.