Answer:
endosymbiosis.
Explanation:
By the beginning of the 20th century, researchers thought that plastids and mitochondria could come from bacteria. These would have been ingested by primitive cells and live within them in symbiosis.
 
        
             
        
        
        
<span>I think this is partly true and partly false. It is partly true because plants undergo in a process called photosynthesis and it is sunlight that makes them do this. It is partly not true because literally the sunlight can't be considered a food source because it actually don't give you food.</span>
        
                    
             
        
        
        
Answer:
The fix nitrogen into free nitrogen which is a usable form. They also bring nitrogen back into the system by decomposing dead organisms.
Answer 2. 
Because, they are known as nitrogen fixing bacteria. These organisms convert nitrogen in the soil to ammonia, which can then be taken up by plants. After nitrogen has been fixed, other bacteria convert it into nitrate, in a process known as nitrification.
Both answer is correct choose the best choice for you.
Hope this helps!
        
             
        
        
        
It takes the Earth (approximately) 364.25 days to revolve around the sun. That's why we have leap days. 
Hope that helps!
 
        
                    
             
        
        
        
Answer: When a plant or animal dies, or an animal voids waste products, the initial form of nitrogen is organic. Bacteria and fungi in the soil produce enzymes that convert the organic nitrogen back into inorganic ammonium ions (NH4 +). Ammonium is converted to nitrite ions (NO2 -) by soil bacteria like Nitrosomonas
Explanation: Hope it helps
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