Question: During the Siberian summer, reindeer graze on young roots, fungi, grass, and other vegetation. In the cold winter months, they migrate south and rely on available, but less nutritious food, such as lichen. Increased snowfall during the entire winter in southern areas would result in reindeer having to

  Options: 
 A. return to their summer feeding area.
 B. hibernate until the snows have stopped.
 C. hunt for organisms such as small rodents.
 D. move to other areas to compete for resources.
Answer: D