Solar winds blow over considerable distances from the Sun. Mercury is the planet closest to the Sun in the Solar System. It is also the smallest of all the planets. How do these factors affect Mercury's atmosphere compared to other planets?
A.
Mercury's atmosphere is thin only at the poles, unlike that of the other planets.
B.
Mercury's atmosphere has more oxygen than other planets.
C.
Mercury's atmosphere is thicker than that of other planets.
D.
Mercury's atmosphere is thinner than that of other planets.

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.

i would say