Question

which feathers help to insulate a bird in cold temperatures? both down and contour feathers contour feathers down feathers ectotherm feathers

Explanation:

To determine which feathers insulate birds in cold temperatures, we analyze each option:

• "Both down and contour feathers": Contour feathers mainly aid in flight and streamlining, not primary insulation. So this is incorrect.
• "Contour feathers": As noted, their role is more about flight and appearance, not insulation. Incorrect.
• "Down feathers": Down feathers are fine, fluffy, and trap air close to the bird's body, providing excellent insulation against cold. This matches their function.
• "Ectotherm feathers": Ectotherms are organisms that rely on external heat (e.g., reptiles), and birds are endotherms. There's no such thing as "ectotherm feathers" for insulation. Incorrect.

Answer:

C. Down feathers