If there were no atmosphere, the sky would be all black, except for the area directly around the sun, which you would not be able to look anywhere near because it would be so bright, as there would be no atmosphere to block its rays.
Contagion and contagiousness refers to how easily the spread of Genetic Disease is possible from one person to another. Other words for contagion include infection, infectiousness, transmission or transmissability. Contagiousness has nothing to do with genetics or inheriting diseases from parents.
Explain the difference between communicable and noncommunicable infectious diseases. 1  communicable disease: a disease in which the invading microbe can be transferred from person to person. noncommunicable disease: A disease that is not transmitted from one host to another.