Answer: 
Nervous: carries messages
muscular: moves the body
epithelium: found in cartilage
connective: found in cartilage 
Explanation:
 
        
                    
             
        
        
        
Answer:
When it stands the test of time and is supported by many experiments.
 
        
             
        
        
        
Natural changed to the ecosystem relate to environmental shock that occur naturally. Natural changes include floods, volcanic activity, hurricanes, etc. They can be destructive, but they also have advantages. Floods have the contribution of nutrients to the soil which was lacking. It can also relocate fishes and organisms living in bodies of water which improves the ecosystem.
        
             
        
        
        
1st stage, also known as the Krebs cycle, also know as the citric acid cycle