What protective structure do bees build to house their brood?

Bees construct brood frames or comb to provide a safe and organized environment for their brood, which includes eggs, larvae, and pupae. The comb consists of hexagonal wax cells that are precisely built to store brood, honey, and pollen, depending on the needs of the colony. Specifically for brood, the cells are designed to be the perfect size for larvae to develop, allowing for optimal growth and protection. The structure of the comb also facilitates ventilation and temperature regulation, which are crucial for the health of the developing bees.

In contrast, while wax cells are part of the comb structure, they do not encompass the full protective framework used for brood housing. Pollen baskets are specialized structures on worker bees for transporting pollen back to the hive and are not involved in housing brood. Honey cells are used specifically for storing honey rather than brood. Thus, brood frames or comb represent the correct answer as they specifically address the structures built for nurturing bee offspring within the hive.