Answer:
Built a great navy and eventually conquered the Romans.
Step-by-step explanation:
Proof : The Roman era of Greek history began with the Corinthian defeat in the Battle of Corinth in 146 BC. However, before the Achaean War, the Roman Republic had been steadily gaining control of mainland Greece by defeating the Kingdom of Macedon in a series of conflicts known as the Macedonian Wars.
Second one is wrong cause - Invention of the submarine. Leonardo da Vinci (1452-1519) made sketches of a submarine and William Bourne, a British mathematician, drew plans for a submarine in 1578. But it was only in 1620 that Cornelis van Drebbel, a Dutch inventor, managed to build a navigable submarine.