Close to Critical planet's air is a little less than the density of liquid water will the raindrops descend slowly; otherwise, they would come down like meteors and make life on Tenebra impossible. But life is possible on Tenebra. Although Clement doesn't say so explicitly, Tenebra's plants do not use photosynthesis. The optical depth of the atmosphere is too great for enough of Altair's light to reach the ground. Instead, Tenebra's plants use chemosynthesis based on the transformation of sulphur oxides. The process is much like that used by plants growing around the hydrothermal vents known as black smokers on the bottom of
Photosynthesis the newly formed NADPH and releases three-carbon sugars, which are later combined to form sucrose and starch. The overall equation for the light-independent reactions in green plants is Carbon fixation produces the intermediate three-carbon sugar product, which is then converted into the final carbohydrate products. The simple carbon sugars produced by photosynthesis are then used in the forming of other organic compounds, such as the building material cellulose, the precursors for lipid and amino acid biosynthesis, or as a fuel in cellular respiration. The latter occurs not only in plants but also in animals when the energy from plants is