Answer 1

Which sentence do you need explained?
"C++ offer a rich assortment...." Means that there are a lot of different variable types, not just int, char, float, etc.... You can also define your own new variable type.

"Creating a variable reserves a memory location..." I think of this as planning a carpark. You know you need each car to have a space, but you don't yet know what colour of car will be in that space, nor who will be in the car. You might know that it's not going to be a car, instead it might be a bus that needs more space, or a fleet of cars that might be 8 cars or might become more....

Answer 2

These lines tells that everytime you declare a variable whether it is inbuilt like int, char, float,double or used-defined like struct you have specify the data type as integer or character or string