the mitochondria provides energy 
 
        
             
        
        
        
Answer:
Looking for light
Explanation:
Since plants require sunlight in order to produce light, they need to be exposed to it. Now, since there are other plants attempting to do the same they have to grow higher so they don't get put in the others shadow and possibly die due to lack of sunlight.
 
        
             
        
        
        
Answer AND Explanation:
Darwin describes natural selection as a process whereby nature selects those organisms that have favourable characteristics to be parents of the next generation. The individuals possessing the favourable traits are better suited to the prevailing environmental conditions. This enables them to stand a better chance to survive in the struggle for existence due to limited resources.
 
        
             
        
        
        
Answer:
Amphibians
Explanation:
They had just shown up during the Carboniferous period and were still living in the water.