The four fundamental forces of nature were Gravity, Electromagnetism, Weak Nuclear force, and Strong Nuclear force. [1]
All along, Adam's first objective was to have control over one of those forces.
In theory, any power of nature taken to the extreme could change the surface. A simple breeze could become a tornado, ice, and snow could bring the ice age. The calm sea could become a Tsunami or the stable earth brings Earthquakes.
Out of the four main forces, the reason why Adam chose Gravity was that in a way, it was the weakest out of them all at the start.
But it was also the most versatile and useful for him from the get-to-go as it would be very useful with his Telekinetic power.
He would even be able to fly if he could lower the gravity around his body and by controlling gravity, Adam would be less helpless if facing someone in close combat.
In the same way, while gravity was the weakest force at the atomic level, it was the strongest force at the astronomical scale.
