Question

smooth muscles are...
not under our conscious control.
responsible for the heart pumping blood.
responsible for the heart oxygenating blood.
under our conscious control.

Explanation:

Smooth muscles are involuntary, meaning they are not under conscious control. Cardiac muscle (not smooth muscle) is responsible for the heart pumping blood, and the heart doesn't oxygenate blood (the lungs do that). So the correct statement about smooth muscles is that they are not under our conscious control.

Answer:

A. not under our conscious control.