What is the main cause of global convection currents? A. Deforestation

B. The Greenhouse effect

C. The increase in the number of cities

D. Uneven heating of the Earth by the sun

Some liquids can be distilled, but only at temperatures that are so high that it is impractical, or so high the compound decomposes. explain why distillation such compounds at significantly less than atmospheric pressure (some degree of vacuum) would solve this problem.