The most important factor contributing to a high infant mortality rate is usually ____.

Giant African millipedes often serve as the home for small mites that scavenge organic matter, but the millipedes do not appear to be affected by the interaction. This is an example of ____.

The greatest damage to species habitat is occurring in ____.

In economically more-developed countries, families tend to have more children because they have more money for education.

Proponents of pesticides claim that they provide some advantages, primarily by ____.

What is the most likely source of thermal pollution in bodies of water?

A habitat’s carrying capacity is largely limited by ____.

What causes cultural eutrophication?

In a grassland food chain, which organism represents the primary consumer?

The most common gas in the atmosphere is ____.