The experiments by Hershey and Chase helped confirm that DNA was the hereditary material on the basis of the finding that:

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.

a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.

the cost of mining is extremely low compared to the money earned from mining, creating income to improve the environment.