Engineer is related to Machine in the same way as Doctor is related to

Choose the correct alternative for the word belongs to the same group.

Which of the following is the same as Rabbit, Rat, Mole ?

Boat is related to Sails in the same way as Balloon is related to

Choose the correct alternative for the given relation.

Bird : Wings

Choose the correct alternative for the given relation.

Giggle : Titter : Guffaw

Which one of the following will come at the place of question mark $(?)$
$25 : 630 :\, : 10 :$ ?