Which of the following does NOT coil or roll up when disturbed?

The correct understanding hinges on the behavior of the organisms in question. Pill bugs, also known as roly-polies, have the ability to roll into a ball when disturbed, a defensive mechanism that protects them from predators. Millipedes can also exhibit a coiling or rolling behavior, typically curling into a tight spiral when threatened.

In contrast, centipedes do not possess this coiling or rolling behavior. Instead, when disturbed, they tend to flee rather than curl up. They are fast-moving predators equipped with venomous bite capabilities, which makes their primary defensive tactic one of mobility rather than rolling up.

Recognizing these behavioral traits helps clarify why centipedes are the only group listed that does not coil or roll up when disturbed, setting them apart from the pill bugs and millipedes.