Final answer:
Reducing heart rate during a dive helps animals stay underwater longer by conserving oxygen and redirecting blood flow to vital organs.
Step-by-step explanation:
The reduction in heart rate during a dive enables animals to stay underwater longer as part of the diving reflex. This reflex diverts blood to essential organs while submerged. When the heart rate slows down, it conserves oxygen and directs more blood flow to critical organs, helping the animal to stay submerged for extended periods.
For example, in marine mammals like whales and seals, the diving reflex reduces heart rate and shunts blood preferentially to the brain and other vital organs, allowing them to conserve oxygen and stay underwater for extended periods.
By reducing heart rate, animals can stay underwater longer by minimizing oxygen consumption and redirecting blood flow to important organs.