<span>Both photoautotrophs and chemoautotrophs synthesize organic compounds from (inorganic) carbon dioxide, a process known as carbon fixation. Photoautotrophs get the energy to perform these reactions from light. Chemoautotrophs get it from electron donors such as hydrogen sulfide and ammonia. Cyanobacteria, by contrast, convert nitrogen from the atmosphere into ammonia, a process known as nitrogen fixation.</span>
The answer regarding the components of an arthropod's nervous system would be item C. It consists of brain, nerve chord, and ganglia. The brain is located dorsally, while the nerve cord together with the ganglia is ventrally structured — extending on each segment of an arthropod’s body.
