False , folic acid is not necessary for making ergosterol.
Explanation:
Folic acid is converted to folate by human body when it is taken as dietary supplement. Main function of the folic acid is to help in making of DNA and RNA, and also helps to metabolise amino acid,that is used in cell division.
Certain fungi like Aspergillus,Penicillum, Cladosporium are commercially grown to extract ergosterol and which can be converted into vitamin D used as dietary supplement and food additive.