What I Have Learned To sum it up, let us complete the statements. Choose your answer from the box that beat completes the statements below. universal set null set subset 1 ) or @ cardinality of set union of set 1. A set with no element is an empty set or 2. The number of elements in the set refers to 3. The consideration, U is the set that contains all objects under 4. If every element in A is also an element in B, then A is a of B. 5. The symbol for empty set or null set is​