What is the definition of a teratogen?

A teratogen is defined as any substance or factor that can cause developmental abnormalities or birth defects in a developing fetus. This can include chemical agents, infectious organisms, and environmental factors that may interfere with normal fetal development during pregnancy. The correct response highlights the critical nature of teratogens in teratology, the study of congenital malformations and the effects of environmental factors on development, which is crucial for public health and safety. Understanding teratogens is essential for minimizing risks during pregnancy and ensuring healthy developmental outcomes for children. The other options describe substances with very different roles and effects, underscoring the importance of knowing specific definitions in the context of health and safety.