Identify the controlled variable

Which sequence correctly shows the path of carbon dioxide during repiration?

You arrive late to a biological seminar. however, just as you enter the room, you hear the speaker referring to the "five-prime end" and the "three-prime end" of a macromolecule. immediately, you know that they are talking about a: ]

Why do some dna fragments move farther than others during gel electrophoresis? a. because their shapes are different b. because they are different types of molecules c. because the samples are different colors d. because their masses are different