Why are transfer of control control instructions needed?

Answer 1

among the most important are

1) in the practical use of computers, it is essential to be able to execute each instruction more than once and perhaps many thousand of times. it may require thousand or perhaps millilions of instructions to implement the instruction. This would be unthinkable if each instruction had to be written out seperately. If a table or a list of items is to be processed, a program loop is needed. once sequence of instruction is executed repeatedly to process all the data

2) virtually all the program involve some decision making. We would like the computer to do one thing if one condition holds, and another thing if another condition holds.

3) to compose correctly a large or even medium sized computer program is an exceedingly difficult task