If a sound is refracted away from the surface of the earth, this indicates that the a. air is cooler than the ground. b. wind is blowing in the direction of the sound. c. ground is cooling faster than the air. d. air has high humidity.

The correct answer is option A, that is, air is cooler than the ground.

Explanation:

Refraction refers to a phenomenon in which there is a modification in the direction of propagation of any wave as a consequence of its mediating at distinct velocities and at distinct points along the wavefront.  In case, when a sound from s source is refracted away from the Earth's surface, there is an indication that the air present above is cooler in comparison to the ground making the sound to refract towards the less dense medium.

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 most common type of reef is the fringing reef. this type of reef grows seaward directly from the shore. they form borders along the shoreline and surrounding islands.