How many moles of nitrogen gas are there in 6.8 liters at room temperature and pressure (293 k and 100 kpa)?

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.

i think it is true since you can test the answer and can use observations to complete it.