As a map reader, when you encounter choropleth maps or proportional symbols maps in which numerical data have been grouped into categories with specific ranges of data, why do you need to be cautious in your interpretation of the map?

A) If the map has been classified using the quantiles method, extreme values (outliers) are likely to be hidden, making these extremes appear to not differ from other values.
B) If the map has been classified using equal intervals, many locations may be lumped into the same category and look identical on the map, hiding what may be distinct differences among places.
C) If you cannot tell which classification method was used, there is a possibility that the map maker has selected category ranges specifically to make the map appear to depict spatial patterns favored by the map makers when there are really no patterns in the data.
D) All of the above.

number of electrons for neutral cl

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.