The genetic information in human and chimpanzee dna shows a high degree of similarity, as humans share about 96-99% of their dna code with chimpanzees. what is an explanation for this similarity?

This similarity can be explained by Charles Darwin's Theory of Evolution. Humans and chimpanzees share a common ancestor wherein a number of million years ago, due to adaptation of their environment, human species branched out and eventually evolved into Homo sapiens. 

The correct answer would be common ancestry.

Common ancestry means that different species have been established from a single parent species or population.

Organisms which share more recent common ancestors tend to have more similarity as compared to the organisms which share an older ancestor.

Humans and chimpanzees also believed to evolved from a common ancestor around 6-7 million years ago.

It is the reason why humans and chimpanzees share around 96-99 percent of the DNA.

the truman doctrine was an american foreign policy whose stated purpose was to counter soviet geopolitical expansion during the cold war. it was announced to congress by president harry s. truman on march 12, 1947, and further developed on july 12, 1948, when he pledged to contain threats to greece and turkey.

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.