Why are beavers called
nature's architects?

Beavers are the great architects of American ponds and streams. Beaver incisors never stop growing, and are self sharpening. The outer edge of the incisor is coated with hard enamel, while the inside is softer and wears down, keeping the cutting edge super sharp.

Explanation:

the roman republic began to expand when rome fought the punic wars and defeated carthage. the punic wars refer to the series of 3 wars fought among rome and carthage, before it ended in carthage's defeat.