How do i design a controlled experiment to appropriately test a hypothesis?

you need only one independent variable because if not, you wont know what factors have changed your experiment.

Explanation:

sup bro, im dumb, but this is what i found xd

"the ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (uvr) from the sun, protecting life on earth from its potentially harmful effects. when the sky is clear, there is an inverse relationship between stratospheric ozone and solar uvr measured at the earth's surface"