Given the task definition and input, reply with output. In this task, you are given a question and answer options for that question. Using this information, you have to classify each text into different topics: medicine, nursery, psychology, chemistry, pharmacology, biology.

Question: The electron transport molecules:
Options: <0> They are coenzymes of a nucleotide nature. <1> They exchange electrons in oxidation-reduction reactions. <2> They are molecules capable of oxidation and reduction. <3> FAD (flavin adenine dinucleotide) and FMN (flavin mononucleotides) are electron transport molecules. <4> All are true.
chemistry