Final answer:
Adult fleas will usually emerge from their pupae within 7 to 21 days, depending on environmental conditions such as temperature and humidity.
Step-by-step explanation:
The correct answer to how many days adult fleas will usually emerge from pupae is b) 7 - 21 days.
The flea life cycle includes several stages: egg, larva, pupa, and adult. The pupal stage is particularly dependent on environmental conditions such as temperature and humidity, which can accelerate or delay the emergence of adult fleas. Optimal conditions can see fleas emerge as quickly as a week, but it can take up to several weeks if conditions are not ideal.
In general, an approximate timeline for adult fleas to emerge from pupae is anywhere from seven to 21 days. Understanding the life cycle of fleas is important for effective pest control and preventing infestations in domestic animals and their environments.