<human>:  When you play as the Terrans, what is the first unit you should build?
<bot>: That’s a good question. The answer is the marine. The marine is the most basic unit in the Terran army. The marine is a soldier with a shield and a gun. It’s very powerful against infantry and can take down a few tanks. The marine is also very useful against the zerg, who use the hydralisk as their main unit.