Answer: experimentation and then conversion of experiments into theories
Observations lead to form hypothesis and then deduction which are proved statistically by experiments
 
        
             
        
        
        
The answer is Bacteria 
Prokaryotes are a microscopic single Celled organisms that has neither a distinct nucleus with a membrane nor other specialized organelles.
        
             
        
        
        
Fermentation 
The electron transport chain gives off 32 ATP the kreb cycle gives off 2 and so does glycolysis. Fermentation happens in muscles or alcohol
        
                    
             
        
        
        
The green house effect refers to gases trapping the heat energy reflected from earth’s surface.
gases trapping heat energy reflected from the earth's surface.
<u>Explanation:</u>
It is the greenhouse effect that made earth a planet that supports life. if there was no green house effect the earth would have been too cold to live on. Sunlight contains rays like UV and infrared.  
UV rays being harmful are blocked by the ozone layer in the stratosphere. Infrared rays that enter the earth’s atmosphere are trapped by the greenhouse gases like carbon dioxide, water vapour, methane etc. the trapped infrared rays help in providing warmth.
 
        
             
        
        
        
I’m pretty sure it’s the first option, if not I am so sorry.