What ideas were changing in the scientific community at the time of Darwin's travels? How might those new ideas have influenced Darwin?

i believe your answer would be c.. : )

answer;

a. sheep consumption efficiency would be reduced.

explanation;

-trophic efficiency is a measure of how much energy occurs at one level divided by the energy at the level immediately below it . trophic efficiency incorporates three types of efficiency:

-the proportion of available energy that is consumed (consumption efficiency).   it is the proportion of the available biomass that is ingested by consumers.

-the proportion of ingested food that is assimilated (assimilation efficiency).

-the proportion of assimilated food that goes into new consumer biomass (production efficiency).

-in this case, the grasshoppers would affect sheep by reducing the proportion of the available biomass that is ingested by the sheep.