Birds share many similarities with a certain group of dinosaurs that includes the Tyrannosaurus Rex and the Velociraptor. Like birds, these dinosaurs had hollow bones and scales. Fossil evidence shows that many had feathers and some could fly. Evidence also suggests these dinosaurs were warm-blooded. Given the similarities, identify one characteristic that could be used to differentiate birds from dinosaurs.

This characteristic to differentiate birds from dinosaurs will be that  Dinosaurs had teeth, and modern birds have beaks.

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 principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.