DNA and gene changes resulting in birth defects in infants are an example of which type of toxic effect?

The correct choice regarding DNA and gene changes resulting in birth defects in infants is indeed teratogenic. Teratogenic effects are those that specifically result in abnormal development of an embryo or fetus, leading to birth defects. These effects are often the result of exposure to certain chemicals, drugs, or environmental factors during critical periods of fetal development.

In this context, teratogens can interfere with the normal development of cells and tissues, leading to structural or functional abnormalities, which can manifest as physical malformations, growth deficiencies, or neurological impairments in the newborn.

The other types of toxic effects do not specifically account for the development of birth defects. Biochemical effects typically refer to changes at the biochemical level that might affect cellular function but are not directly linked to malformations. Carcinogenic effects relate to substances that increase the risk of cancer, which is different from birth defects. Mutagenic effects involve changes to the genetic material that could lead to mutations; while they may play a role in causing future issues, they are not directly synonymous with the developmental issues seen in teratogenic effects. Thus, understanding these classifications helps clarify the impact of various substances on human health, especially during the vulnerable stages of development.