Fermentation occurs in anaerobic respiration, and produces less energy than in aerobic respiration due to the lack of ETC because oxygen is not present.
        
             
        
        
        
Answer:
Photosynthesis is the process where green plants synthesis energy using the energy of the sun, carbon dioxide and water.  Photosynthesis is very important to life it keeps most plants alive (autotrophs), and heterotrophs eat autotrophs to help them het energy. An autotroph is an organism that synthesis its own energy and heterotroph is an organism that gets it energy by digesting other organisms. 
 
        
             
        
        
        
White blood cells fight disease
        
                    
             
        
        
        
Answer:
Nervous system
Explanation:
The nervous system in humans work together to collect information about the external environment because they consist of the brain, spinal cords and neurons. They collect information from external environment and those information travels through neurons from sense organs like eyes, ears, skin e.t.c as a form of electrical impulses. When they get to the end of the neuron, a chemical called neurotransmitters are released which travels across the cells and send it to the brain, the brain then process it and interprete the signals and respond to it as stimulus.