Hello! THere are many differences between a grassland and a savanna. For one, a savanna is a grassland, however, A savanna is usually very dry. A savanna also has very few trees, while grasslands can be plush with many trees. Grasslands could also be in mountains while savannas are vast dryer lands with animals who live in dry weather. Grasslands also contain a lot of water sources like lakes, rivers, ponds, and savannas usually don't. Those are just a few o the many differences between them! 
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I am, yours most sincerely,
SuperHelperThingy
        
             
        
        
        
CO2 is considered organic because it doesn’t contain a hydrogen. Organic compounds must contain carbon bound to hydrogen and possibly other elements.
        
                    
             
        
        
        
Every plant organ is adapted to its function. For example, leaves that are big and flat absorb plenty of sunlight for photosynthesis. Long roots keep a tree stable and take water from deep in the soil. Some plants have unusual adaptations.
        
             
        
        
        
The answer is They help control what enters and leaves the cell