Which type of ant is sterile and performs work for the colony?

The worker ant is a sterile female that is crucial for the functioning of the colony. These ants are responsible for various essential tasks, including foraging for food, caring for the queen's offspring, maintaining the nest, and defending the colony. Worker ants do not reproduce; instead, their role is entirely dedicated to supporting the colony's survival and growth.

In contrast, the queen ant is responsible for reproduction and is not involved in the labor tasks that the worker ants perform. Drone ants, which are male ants, exist solely to mate with the queen and do not contribute to the work of the colony. Therefore, the unique role of the worker ant as a non-reproductive individual dedicated to the colony's needs highlights why this choice is the correct answer. The sterile nature of worker ants allows them to channel their energy into supporting the communal needs of the colony.