What helped the Mycenaeans develop a powerful civilization? They invented an alphabet for writing.
They constructed strong cities with walls.
They built labyrinths with spiritual meanings.
They made a purple dye for creating goods.

Correct answer is They constructed strong cities with walls.

Explanation:

This option is correct because when Heinrich Schliemann discovered well equipped graves near the lion gate at Mycenae, it confirmed Homer's description of the city "rich and gold". Lion gate was one of the entrances to the city that was encircled by strong walls.

First option is not correct as alphabet already existed, and it is not their discovery.

Third option is not correct and it is more connected with Cretan civilization.

Last option is also not correct, and is more connected to Phoenicia for example.

~kinetic ~potential

explanation:

kinetic and potential energies would be types of mechanical energies.

your answer is "graduates" hope this