ANSWER : Only one super type

Explanation : In a super type/subtype hierarchy, each subtype has only one super type

ANSWER : Attribute

Explanation : A property or characteristic of an entity type that is of interest to the organization is called attribute

ANSWER : The left side of the tree

Explanation : The hierarchical database model uses the hierarchic sequence that always starts at the left side of the tree

ANSWER : Unary.

Explanation : A relationship between the instances of a single entity type is called a Unary relationship.