Why are baits considered ready to use?

Baits are considered ready to use because they do not require any preparation before application. This means that users can apply them directly in their existing form without needing to mix, dilute, or prepare them in any way. This convenience is crucial for effective pest control, as it allows for quick and straightforward application, ensuring that the bait can be placed in areas where pests are active without delay.

The other choices imply various characteristics that do not define the 'readiness' of baits. While some baits may be effective against certain types of pests, they are not necessarily effective against all, which disqualifies the option suggesting they work on every pest. Additionally, the mention of needing mixing or preparation contradicts the definition of a 'ready to use' product. Lastly, pre-measured powdered forms could be a characteristic of some baits, but this does not encompass all baits universally, as many come in different formulations that don’t require preparation at all. Therefore, the defining factor of being ready to use is that they are immediately applicable without further action needed from the user.