When you hear the word respiration, you may automatically think about breathing. Explain how this type of respiration (breathing) is related to cellular respiration. What type of respiration would occur if a
person were to hold his or her breath? Which by-product will build up in this situation?

he is very short, and he can only reach halfway up on the elevator buttons. but on a rainy day, he has his umbrella with him, and he uses it to poke the button at the top.

not only is it colder, it also becomes darker, less salty, and more dense.

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.