Which logical fallacy is used in the text?
Before I refute my opponent's argument, I would like to draw attention to the fact that he is sweating and clearly does not have much experience on the debate team.

 - ad hominem: an attack against the person making the argument, rather than the argument itself
 - bandwagon fallacy: the assumption that the popular choice is automatically correct
 - appeal to nature: the assumption that natural things are always good
The text argues that the speaker's debate opponent is sweaty and inexperienced. This is a personal attack that isn't relevant to whether the opponent's argument is valid. This illustrates a type of logical fallacy known as ad hominem.