Yes but one is inferred by the other, you cant "ground" the ball without having a controlled grip on the ball.
I disagree, and so does the Law. You can ground the ball without control, but it depends in whether you have possession of the ball or not.
If you have the ball in your possession then you only need ground the ball
[TEXTAREA]22.1 GROUNDING THE BALL
(a) Player touches the ground with the ball. A player grounds the ball by holding the ball and
touching the ground with it, in in-goal. ‘Holding’ means holding in the hand or hands, or in
the arm or arms. No downward pressure is required.[/TEXTAREA]
If the ball is loose, then you need to ground it with downward pressure
[TEXTAREA]22.1 GROUNDING THE BALL
(b) Player presses down on the ball. A player grounds the ball when it is on the ground in the
in-goal and
the player presses down on it with a hand or hands, arm or arms, or the front of
the player’s body from waist to neck inclusive.
[/TEXTAREA]
If you've lost control of the ball you've knocked on before it's down, so no try. Simples.
No, a player can lose control of the ball backwards and still ground the ball for a try.