Athletes who exercise regularly are able to exercise for longer, ...

[karen]

Athletes who exercise regularly are able to exercise for longer, partly because their body uses more energy from
 
  a. fat.
  b. protein.
  c. amino acids.
  d. carbohydrates.

Question 2

When an athlete eats more protein or amino acids than he or she needs, the extra amino acids are
 
  a. stored in the amino acid pool.
  b. used to increase muscle mass.
  c. converted to storage protein by the liver.
  d. deaminated and used as an energy source.

[DylanD1323]

Answer to Question 1

A
Regular exercise increases the body's ability to use energy from fat. This spares glycogen stores and exercise can continue for longer. Protein and amino acids are used only when glycogen and glucose (carbohydrate) stores are exhausted; this would take longer in athletes who exercise reg-ularly.

Answer to Question 2

D
Excess amino acids are deaminated and used as an energy source. The body cannot store amino acids or protein and only increases muscle mass in response to exercise.