What is a teratogen?

A teratogen is defined as an agent capable of producing abnormalities in embryos, which is why the choice describing it as such is correct. Teratogens can cause malformations during the development of embryos or fetuses, leading to various birth defects. This impact on developmental biology is a critical concern in toxicology, especially when considering the exposure of pregnant individuals to harmful substances, including certain chemicals, drugs, and environmental agents.

The other options do not relate to the definition of a teratogen. Increasing pest resistance refers to a strategy in pest management rather than a developmental concern. Enhancing pesticide effectiveness focuses on improving how pesticides work against pests, without any relation to embryonic development. Similarly, targeting overgrowth in plants pertains to plant health and management, rather than the effects of substances on developing organisms. Therefore, understanding teratogens is essential in contexts where exposure to substances during pregnancy may pose risks to fetal development.