Fiil in the blanks with lowercase letters $!!!!!$

Answer

In this question you are presented with $4$ blank fields that you should fill in according to their context. Read the surrounding text first, and then type your answer.

The singleton design pattern is a $\_\_\_\_\_$ pattern that ensures a class has one $\_\_\_\_$ and provides a $\_\_\_\_\_\_$point of access to that instance. This helps to maintain consistency, reduce and ensure better use of resources.

fill the blank