What is a pesticide?

The correct definition of a pesticide is indeed that it is a chemical substance used to kill or control pests. Pesticides are specifically designed to manage populations of organisms that can harm crops, livestock, or human health, which includes a variety of pests such as insects, weeds, fungi, and rodents.

Understanding the role of pesticides is crucial in agriculture and pest management, as these substances can effectively protect crops and ensure food safety. They are formulated to target specific pests while minimizing harm to non-target species and the environment when used according to label instructions.

The other options detail concepts that do not reflect the purpose or function of pesticides. For example, fertilizers promote plant growth rather than controlling pests, natural products may have pesticide properties but are not inherently classified as pesticides, and food additives serve a different function related to preservation rather than pest control. This clarification helps highlight the unique role pesticides play in agricultural practices.