Which are typical pioneer species during primary succession?

Answer & explanation:

Primary succession occurs in environments that did not have biological communities in place and present unfavorable conditions for the establishment of life. Examples of these sites are rocks, dunes and newly solidified lava pits.

The pioneer organisms in primary succession are mainly producers and some decomposers.

In dune environments, for example, there are grasses, whose seeds are wind-borne and able to withstand excessive heat, water scarcity and unstable soil, and their roots are firm, preventing these plants from being harmed by the wind.

Sites with rocky surfaces can be colonized by photosynthetic bacteria, fungi or some species of algae. These organisms release substances that alter the substrate, allowing the installation of new species over time.

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.

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.