What does the ozone do for us? as in us humans?

What is the wavelength of a wave with a velocity of 50 m/s and a frequency of 5hz a 250 m b 0.1 m c 10m d 0.01 m

Which best describes the present-day universe? opaque, expanding very slowly, stars produce heavy elements transparent, expanding at an accelerated rate, stars produce heavy elements opaque, expanding at an accelerated rate, stars produce only hydrogen and helium transparent, expanding very slowly, stars produce only hydrogen and helium

What would happen if no were added to n(g)+o2=2no(g) at equilibrium?