Additive color mixing involves multiple sources of light with different colors in each source. Subtractive color mixing involves a single source of light with different colors absorbing various wavelengths of the color spectrum. Secondary colors of one system serve as the primary colors for the other.
Gas.
The sky is not solid, not liquid but of gas. It is also
called the atmosphere, one of the important spheres on earth that influences
the climate –temperature, humidity, precipitation, atmospheric pressure, and
the biotic community as a whole. The atmosphere or the sky is composed of many
layers and is responsible to protecting the living organisms of the earth
against the deadly ultraviolet rays and other strong radiation coming from the
sun.
The oxidation half reaction of the reaction given above would be: Ca → Ca + 2e−. Oxidation is the loss of electrons of an element while its counterpart is called the reduction which gains the electrons that has been lost. Hope this answers the question.
The troposphere protect the molecules because there are higher layers on top. This makes life possible on Earth.