Penguins that are able to survive the extremely harsh winters in the icy lands of Antarctica do so by huddling together in tightly packed groups. They do this because they are depending on each other to meet their need for a certain -

a. nutritional requirement.
b. quantity of fresh water.
c. range of temperatures.
d. duration of sunlight.

C. range of temperatures.

Explanation:

To prevent themselves freezing to death, they huddle together in tightly-packed groups to conserve heat and shelter themselves from the intense winds.

b is dominant over the allele for the white fur.

producers: apple trees, potatoes, carrots, grains, acorns, cabbage, grass, corn, lettuce

consumers: deer, mice, rabbits, chickens, squirrels, horses, worms, cows

predators: eagles, frogs, wolves, owls