Which of the following is created when the sun pushes the ionized gases of a comet away from the central core?
coma
nucleus
plasma tail < -- my answer
solar wind

Plasma tail

Explanation:

A comet is a body in space which revolves around Sun in elliptical orbit. It is composed of rocks, dust, ice and frozen gases. A comet has mainly three parts:

Nucleus- It is the core of the comet which is solid.

As the comet nears the sun, the frozen gases start sublimating. An atmosphere surrounds the nucleus which is known as coma.

As the comet approaches the sun closely, the coma extends backwards due to solar wind. The solar wind pushes the ionized gases of the comet away from the nucleus. This is known as tail. There are two tails - dust tail and  plasma tail. Plasma tail is composed of ionized gases -heavier than the dust tail and thus lies below it.

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.