A population of deer existed for centuries in a hilly region of England. The landowners decided to introduce sheep into the same area. Deer and
sheep eat some of the same kinds of plants. After the sheep were
introduced, the deer population began to decline. How could the decline in
the deer population be explained?
A. Sheep competed with the deer.
B. The sheep were smaller than the deer.
C. The food web became too complex.
D. Sheep are at a higher trophic level than deer.