Question

Gulls, ducks, and geese can stand on ice without freezing their feet because of this adaptation:

Select one:
a. in the fall a thick layer of down and contour feathers covers the feet, keeping them warmer in winter
b. more blood is pumped into those extremities to raise their internal temperature
c. a thick layer of white fat develops under the skin in the feet for insulation
d. a counter-current heat exchanger known as the rete mirabile is activated in winter
e. all of the above

Answer 1

Birds like gulls, ducks, and geese use a counter-current heat exchanger system called the rete mirabile to prevent their feet from freezing on ice. The correct option is D.

Step-by-step explanation:

Gulls, ducks, and geese can stand on ice without freezing their feet due to a specialized adaptation. The correct answer to why these birds can stand on ice without their feet freezing is d. a counter-current heat exchanger known as the rete mirabile which is activated in winter.

This biological adaptation allows for the transfer of heat from warm blood flowing down to the extremities back into the cold blood returning to the heart, thus reducing heat loss and preventing the feet from freezing.