The number of degrees of freedom of the planetary gear train shown in the figure is

A wheel of radius r rolls without slipping on a horizontal surface shown below. If the velocity of point P is 10m/s in the horizontal direction, the magnitude of velocity of point Q (in m/s) is ______

A 4-bar mechanism with all revolute pairs has link lengths $${l_f} = 20\,\,mm,\,\,{l_{in}} = 40\,\,mm,\,\,{l_{co}} = 50mm$$ and $${l_{out}} = 60\,mm.$$ The suffixes $$'f', 'in', 'co'$$ and $$'out'$$ denote the fixed link, the input link, the coupler and output link respectively. Which one of the following statements is true about the input and output links?

For the given statements:
($$I.$$) $$\,\,\,$$ Mating spur gear teeth is an example of higher pair
($$II.$$) $$\,\,\,$$ A revolute joint is an example of lower pair.

Indicate the correct answer.