What are pesticides?

Pesticides are specifically defined as chemicals that are used to kill, control, or repel pests, which can include insects, weeds, fungi, and other organisms that may harm crops or livestock. These substances are essential in agricultural practices to protect plants and ensure a good yield. The term "pesticide" encompasses a wide variety of chemical products, including insecticides for insects, herbicides for weeds, fungicides for fungi, and more.

The other options do not accurately reflect what pesticides are. For example, fertilizers are substances that promote plant growth but do not serve the purpose of controlling pests. Similarly, herbal treatments and natural repellents may provide alternative methods for managing plant health or pest control, but they do not fall under the definition of pesticides, which specifically refers to chemical formulations designed with the intent to eliminate or manage pest populations.