Using what you have learned about energy transformations, explain why the driver of a car has to continuously apply pressure to the gas pedal in order to keep the car cruising at a steady speed, even on a flat road. does this situation violate the law of conservation of energy? why or why not?

No this is not violation of energy conservation

Explanation:

When car is moving on flat car then driver has to push the gas pedal so that car will constantly receive the energy from fuel.

Here on flat road car needs constant energy for moving with constant speed on the ground because car is moving on rough ground where it has to work against friction force.

So here the constant energy received from the fuel is used to work against friction force.

So by energy conservation principle we can say

Energy received by fuel = work done against friction force

So here energy conservation principle holds good