Q: 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: Which amino acid serves as a starting point for the synthesis of porphyrins (heme group)?
Options: <0> Valina <1> To the girl. <2> Asparagine <3> Lysine <4> Glycine
A:
chemistry