Answer to the question no : 1
 A binary tree consists of a finite set of nodes that is either empty, or consists of one specially designated node called the root of the binary tree, and the elements of two disjoint binary trees called the left subtree and right subtree of the root.

Answer to the question no : 2
 Full Binary- A full binary tree (sometimes proper binary tree or 2-tree) is a tree in which every node other than the leaves has two children.
Complete Binary- A complete binary tree is a binary tree in which every level, except possibly the last, is completely filled, and all nodes are as far left as possible.