Answer:
Eukaryotic cells arose through endosymbiotic events that gave rise to the energy-producing organelles within the eukaryotic cells such as mitochondria and chloroplasts.
 
        
             
        
        
        
Liquid water, which is necessary for life as we know it, continues to exist on the surface of Earth because the planet is at a distance, known as the habitable zone, far enough from the Sun that it does not lose its water to the runaway greenhouse effect.
        
             
        
        
        
Answer:
D. It release hormones into the bloodstream.
Explanation:
I think.
 
        
             
        
        
        
Answer:
Hard
Explanation:
it is hard because these are usually hard parts of an organism including shells, bones, teeth, woody trunk, stems, and branches.
 
        
             
        
        
        
The best answer would be enzymes since they are protein molecules and help build it. Enzymes also take part in reaction.