The idea that the processes that formed the earth have taken more than thousands of years instead of quickly is known as
catastrophism
punctualism
gradualism
movement
uniformism

Hence, The required answer is GRADUALISM

Step-by-step explanation:  

Catastrophism : It is defined as a theory that produce some changes in the earth's crust with the result of some sudden and unusual events. So, we cannot relate this term to the given fill in the blank statement.  

So, this option is rejected

Punctualism :  It states that the certain structures are effected time to time without violating the standard rules of the structures.

So, this option is also rejected.

Gradualism :   It accounts for the changes that has occurred with the increase in time rather than the sudden or unusual change.

So, The changes in the earth have not occurred suddenly where as it had taken thousand of years for these changes.

Movement :  It is defined as an act of change of object's physical position or location as compared to the initial position of the object.

This also can't be related so rejected

Uniformism : It accounts for all the processes occurring today at the same rate in the same manner as it has occurred in the past.

This also is rejected.

Hence, The required answer is GRADUALISM

answer: 48

just remember to use pemdas:

parentheses

expressions

multiplication

division

addition

subtraction