Me wizards of biology an example of a detritivore would be a. a cow eating grass b. a hawk capturing a mouse c. a colony of ants eating a grasshopper

None of these are examples of detritovore.  A cow eating grass is an example of herbivore.  A hawk capturing a mouse and ants eating a grasshopper are both examples of predation.  I suspect the answer they are looking for is C, but that would only be accurate if the grasshopper were already dead before the ants got to it.  Basically, detritovores are organisms that eat dead things.

a. decomposes use carbon from dead organisms as fuel for cellular respiration, returning carbon dioxide back into the atmosphere.