Question

imagine a man flying with a parachute .name the force which is responsible for his downward motion. will he come down with the same speed without the parachute

Answer 1

Hey there!

The force is gravitational force.
No, he will not come down with the same speed without the parachute as he will fall with a great speed and will die.

Hope it help

Answer 2

the force responsible for his downward motion is gravity
no, as he opened parachute it will create aerodynamic drag which will reduce his speed