Final answer:
The number of senators in the Senate can change when new states are admitted into the United States.
Step-by-step explanation:
The number of senators in the Senate, which is currently 100, can change due to changes in the number of states in the United States. If new states are admitted into the United States they would be represented in the Senate by their own senators. For example, when Alaska and Hawaii were admitted as states in 1959, their two senators were added to the Senate, increasing the total number of senators to 100.