Los organismos unicelulares que utilizan compuestos como las proteínas, carbohidratos y lípidos para obtener la energía necesaria, son los:

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.

well for one plants are always the producer, so a is the answer. a wolf is more of the consumer(predator) and the deer is the prey so i know those two are out of the question. also mushrooms are fungi/fungus so a is the producer.