Which of the following is a group related to insects?

• A. Annelida
• B. Crustacea
• C. Arachnida
• D. Mollusca

Answer: (C)

Insects are part of a larger group called arthropods, which share features like a tough exoskeleton, segmented bodies, and jointed legs. Arachnids are another major subgroup within arthropods, including spiders, scorpions, mites, and ticks. Because they belong to the same broad phylum and share those fundamental features, Arachnida is the group that best fits “related to insects.” The other options aren’t arthropods: Annelida are segmented worms, and Mollusca are mollusks. Crustacea are also arthropods, but the choice here is the standard example used to contrast with insects in many studies.