In animal populations, DDT causes birth defects.

Correct option

From the choices given — birth defects, tuberculosis, sleeping sickness, the flu, malaria — the correct answer is:

  • Birth defects

DDT is a persistent organic pollutant that accumulates in fat tissues and biomagnifies up the food chain, where it disrupts endocrine function and normal development in wildlife, leading to reproductive problems and developmental abnormalities (birth defects) in many animal populations.

It does not directly cause infectious diseases such as tuberculosis, sleeping sickness, the flu, or malaria; those are caused by specific pathogens (bacteria, protozoa, or viruses), not by pesticides like DDT.

So, the best completion of the sentence “in animal populations, DDT causes _____” from the options provided is birth defects.