What characteristics distinguish mites, ticks, spiders, and scorpions from insects?

Mites, ticks, spiders, and scorpions belong to a different class of arthropods known as arachnids, which is a key distinguishing factor from insects. A fundamental characteristic of arachnids is that they possess four pairs of legs (a total of eight legs), as opposed to the six legs that insects have. This unique leg structure is a significant physical distinction between these two groups.

In terms of body structure, arachnids typically have two main body regions: the cephalothorax (the combined head and thorax) and the abdomen. In contrast, insects have three distinct body regions: the head, thorax, and abdomen. This difference in body segmentation is another important characteristic that helps to differentiate arachnids from insects.

Therefore, a combination of having four pairs of legs and two body regions confirms the distinction between these two classes of arthropods. This combination of characteristics reinforces why the accurate answer includes both features outlined in the correct response.