The following information describes a person’s diet:
36% - bread, rice, potatoes, and pasta
35% - fruit and vegetables
12.5% - milk and dairy foods
11% - meat, fish, eggs, and beans
5.5% - foods and drinks that are high in fat and sugar
a. bread, rice, potatoes and pasta form 36% of this diet. which macromolecules are prevalent in these foods? explain why these foods are important to the body. (give at least two examples)
b. state the foods listed above that are rich in protein. why are proteins important to the body? (give at least two examples)
c. only 5.5% of this diet is made up of food and drinks that are high in fat and sugar. describe one harmful effect of eating too much fat.

On a backpacking trip, kenny hikes all day at a steady pace, covering 30 kilometers and burning 4000 calories. at the school track, janelle runs the 100-meter sprint in 13.5 seconds, burning 10 calories. afterward, janelle’s leg muscles are aching and she is breathing hard, while kenny maintains normal breathing all day, even though he burns 400 times more calories than janelle. which two statements offer the best explanation for this phenomenon? a. if the aerobic pathway—cellular respiration—cannot meet the energy demand, then the anaerobic pathway—lactic acid fermentation—starts up, resulting in lactic acid buildup and "oxygen debt." b. aerobic cellular respiration produces more energy, but its use is limited because of lactic acid buildup in the muscles and the resulting "oxygen debt." c. after about 90 seconds of intense exercise, the muscles become depleted of oxygen, and anaerobic respiration can no longer function to produce atp, resulting in "oxygen debt." d. the rate of energy demand determines how the muscles will obtain energy, either from cellular respiration or from lactic acid fermentation if not enough oxygen is present.