a)The rapid depletion of the ozone layers and climate changes adversely affect human beings. Higher temperatures, heavier rainfall, and changes in climate variability would encourage vectors of some infectious diseases. (b1)All of these effects happen because of many factors. (b2)One factor is natural factors that are external to the climate system, such as changes in volcanic activity, solar output, and the Earth's orbit around the Sun. However, (b3) the human activities are the main cause of this problem.