The phrase from the passage that BEST supports his generalization is:
Chimpanzees use tools in the same way humans do.
Explanation:
The primary skill that differentiates humans from other animals is our ability to use tools for our advantage in the wild world. This led the humans to develop more sophisticated tools and then work with them.
The chimps have been known to use simple tools for digging and finding things which is usually wooden and stone tolls they create for their own subsistence. This means that the chimps have the ability to evolve even further and there is a chance that they can develop more sophisticated tools.