What type of pesticide builds up in animals and plant tissues?

The correct answer is accumulative because it refers to pesticides that persist in the environment and can be taken up and stored in the tissues of animals and plants over time. This accumulation can lead to higher concentrations within the organisms than what is present in their surrounding environment, potentially resulting in adverse effects on their health and the ecosystem.

Accumulative pesticides may not break down easily and can remain within an organism's system, leading to long-term exposure and effects that can intensify with continued exposure through food chains. Understanding this concept is crucial for pest control applicators as it highlights the importance of considering the long-term environmental impact and safety of the pesticides they use.

In contrast, biodegradable pesticides break down quickly in the environment, systemic pesticides are absorbed and circulated within a plant, and selective pesticides target specific pests while leaving others unaffected. None of these options align with the notion of persistent accumulation in tissues.