The __________ operator is used to dynamically allocate memory.

Answer: The "new" operator is used for dynamically allocating memory in C++. It allocates memory for an object or an array of objects on the heap and returns a pointer to the allocated memory. The syntax for using 'new' for memory allocation is `new datatype`, where datatype can be any valid C++ data type. For example: `int *ptr = new int;`. It is important to free the allocated memory using the "delete" operator when it is no longer needed to prevent memory leaks, e.g., `delete ptr;`. Dynamic memory allocation is crucial for various programming scenarios like data structures, where the exact amount of required memory is not known at compile time, and the memory can be allocated and deallocated during runtime as needed.