Which of the following describes a study that is “longitudinal”? A study that follows people for an extended period of time to see if they develop a disease or condition. A study that looks at people in one location, to reduce any bias introduced by varying locations. A study that follows people taking a drug or placebo for 6 weeks to see if they develop a disease or condition. A study that follows people taking medication in different locations, to see if their location impacts the medication’s effectiveness.

I'd say it's the first option, A study that follows people for an extended period of time to see if they develop a disease or condition.

Explanation:

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.

increased stability in the completion of fluorine's outer shell.