Cockroaches need ___ to be successful.

Cockroaches are highly adaptable pests that require specific environmental conditions to thrive, and the correct option identifies the essential elements they need. Food is crucial for their survival, as it provides the nutrients necessary for growth and reproduction. Moisture is also vital, as cockroaches can become dehydrated quickly; they typically seek out environments with sufficient humidity to sustain their needs. Lastly, harborage refers to safe, hidden places where cockroaches can rest, breed, and avoid predators. These areas are often dark and provide protection, making them ideal for cockroaches to establish their presence.

The other options contain elements that are either less significant or inaccurate when discussing the specific requirements for cockroach success. For instance, while warmth does play a role, the combination of food, moisture, and harborage most effectively describes the optimal conditions that support cockroaches in their environment.