Migrating birds often cross the Gulf of Mexico in a single flight,and their flight muscles demand extreme endurance.An examination of the muscles used to perform this activity would show that they
A) have low reserves of glycogen (metabolic fuel).
B) have high levels of ATPase activity.
C) are well-supplied with blood vessels.
D) have few mitochondria.
E) have low levels of myoglobin.

Question

Quizplus · Accepted Answer

Muscles that demand endurance require a consistent supply of oxygen and fuel. Therefore, they are typically well-supplied with blood vessels. This would be especially crucial for the flight muscles of migrating birds, which need to cover long distances without rest.

Migrating Birds Often Cross the Gulf of Mexico in a Single