Cells use oxygen to assist in cellular respiration. This type of respiration, called aerobic cellular respiration, converts stored energy into a usable form. The first stage of aerobic cellular respiration, glycolysis, can be performed without oxygen.
A persuasive speech is a specific type of speech in which the speaker has a goal of convincing the audience to accept his or her point of view. The speech is arranged in such a way as to hopefully cause the audience to accept all or part of the expressed view.
A persuasive essay uses reason to demonstrate that certain ideas are more valid than others in academic writing. The purpose of such an essay is to encourage readers to accept a particular viewpoint or act in a particular way.