I think its salinity because the other things have something to do with tracking precipitation
The continual input of energy, mostly from sunlight, sustains the process of life. Sunlight allows plants, algae and cyanobacteria to use photosynthesis to convert carbon dioxide and water into organic compounds like carbohydrates. This process is the fundamental source of organic material in the biosphere. There are a few exceptions to this, such as ecosystems living around hydrothermal vents on the ocean floor, which derive their energy from the chemical compounds such as methane and hydrogen sulfide. In either case, the overall productivity of an ecosystem is controlled by the total energy available.
The answer to number 2 would be as the number of carbon carbon 2ble 2ble bonds increase, the melting point decreases
An example of photosynthesis is how plants convert sugar and energy from water, air and sunlight into energy to grow. The biological synthesis of chemical compounds in the presence of light
