Which of the following best describes a nonselective pesticide?

A nonselective pesticide is defined by its broad-spectrum action, meaning that it is effective against a wide range of organisms rather than targeting specific pests. This characteristic allows it to eliminate various types of plants, weeds, and possibly beneficial organisms indiscriminately. Such versatility is key in situations where complete control over all vegetation is desired, such as in industrial areas or during land preparation for agriculture.

The other choices focus on more specific applications or characteristics. For instance, a pesticide effective only against insects describes a selective approach, while one harmful only to noxious weeds indicates a targeted application, which is the opposite of nonselective action. Additionally, while a pesticide that requires fewer applications could be beneficial, it does not inherently define the selectivity or broad-spectrum nature of the product. Therefore, the characteristic that best encapsulates a nonselective pesticide is indeed its broad-spectrum action.