All the substances which produce undesirable defects in a fetus during prenatal development are called Teratogens
Teratogens refers to those substances that may produce physical or functional defects in the fetus or embryo growing in a pregnant womanafter the pregnant woman has been exposed to suvh substances.
Examples of teratogens include:
Therefore, all the substances which produce undesirable defects in a fetus during prenatal development are called Teratogens.
Learn more about teratogens at: https://brainly.com/question/6676255