Which statement about house dust mites is true?

• A. They require high humidity to thrive.
• B. They are active only at night.
• C. They feed on wood fibers.
• D. They do not require humidity.

Answer: (A)

Dust mites survive and multiply best in moist indoor air. They rely on moisture from the environment to maintain their body fluids and to reproduce, so when relative humidity is high (roughly above 50%, with optimal around 70–80%), their populations grow, especially in bedding, upholstery, and carpets. In drier air, they desiccate and numbers fall; this is why controlling humidity is a common way to lessen mite problems. They don’t feed on wood fibers and their activity isn’t tied to day or night, but rather to whether the environment can support their water balance and food sources (dead skin cells and other organic material). So the true statement is that house dust mites require high humidity to thrive.