Помогите пожалуйста ответить: 11. My first is an empty space in

Помогите пожалуйста ответить: 11. My first is an empty space in something,
But you should omit the last E,
My second is the suffix in the most adverbs,
My whole is the evergreen tree branches of which are used for Christmas decorations.
12. My first is water that falls in small drops from clouds,
But replace the second A into E,
My second and third are fourth and fifth letters from the alphabet,
My fourth is the suffix to form the comparative,
My whole is the animal that helps Santa to travel. 13. My first is the light and heat produced when something burns,
My second is any area or position in space,
My whole is something that let Santa Clause come in.