Using carbo-loading to increase the store of glycogen seems to benefit only those athletes who engage in aerobic activities that are?

This can benefit athletes who perform aerobic activities lasting longer than 90 minutes.

Explanation:

Glycogen is a homopolysaccharide, which means that its molecule is composed of monomers of the same monosaccharide, in this case glucose. It is the main carbohydrate for energy storage in animal cells. In other words, we can say that glycogen is the way glucose is stored in the body for future energy needs.

Many athletes may be influenced to use a carbohydrate load to increase glycogen stores in the body. However, this extra glycogen reserve will only benefit athletes who perform aerobic activities lasting longer than 90 minutes, due to the extra energy expenditure that these activities impose.

                                                        water

a colorless, transparent, odorless, tasteless liquid that forms the seas, lakes, rivers, and rain and is the basis of the fluids of living organisms.

                                                        halon  

any of a number of unreactive gaseous compounds of carbon with bromine and other halogens, used in fire extinguishers, but now known to damage the ozone layer.

                                                  dry chemical

extinguishing agent used on class a, class b, and class c fires.

                                                  carbon dioxide

a colorless, odorless gas produced by burning carbon and organic compounds and by respiration. it is naturally present in air (about 0.03 percent) and is absorbed by plants in photosynthesis.