Answer:
Due to its different parts which require different tools.
Step-by-step explanation:
It is important to have a range of tools that can measure all parts of the electromagnetic spectrum because electromagnetic spectrum have different radiations such as infrared, visible light, ultraviolet, radio waves, microwaves, X-rays and gamma rays. Each of these radiation requires different instrument for their measurement. So that's why a range of tools are needed to measure electromagnetic spectrum.