Question

what do you think if our heart was made by voluntary muscles

Answer 1

voluntary muscles fatigue soon so if heart was made by voluntary muscles our lifetime would be very less and we would die soon

Answer 2

If heart wouldhave made of voluntary muscles , it would have been under the control of our will. But that's absurd bcoz heart is a pumping organ and need to beat continuously in order to supply blood to various part of body. If it was made of voluntary muscle then it would be tired often.

That's y its an involuntary muscles.