Question

why did the aral sea begin to shrink?
the summers became hotter, which caused the water in the aral sea to shrink
an earthquake opened up cracks in the sea floor, allowing the water to flow away from the sea
the soviet government built dams across the two rivers that fed into the aral sea
the amu and syr rivers shifted course, emptying into the caspian sea

Explanation:

The Aral Sea shrank mainly because the Soviet government built dams across the two rivers (Amu Darya and Syr Darya) that fed into it. These dams diverted water for irrigation, reducing the inflow to the Aral Sea. The other options are incorrect: hotter summers alone wouldn't cause such a drastic shrinkage, an earthquake isn't the main cause, and the rivers didn't shift to the Caspian Sea.

Answer:

The Soviet government built dams across the two rivers that fed into the Aral Sea