Answer:
1 and 4
Explanation:
Streams and small rivers flow together to create river systems. As the weather gets warmer, the snow and ice from the winter melts, which makes the water flow down the stream and into the larger river system. ... This can result in flooding due to more water draining in than being lost to evaporation.
 
        
                    
             
        
        
        
Answer:
I've tried to open the attachment but I can't 
Explanation:
please reattach the question 
 
        
             
        
        
        
Answer:
Crude Oil/Petroleum
Explanation:
Crude oil is a very versatile fuel and is used to produce things like plastics, artificial food flavorings, heating oil, petrol, diesel, jet fuel, and propane.
 
        
                    
             
        
        
        
Biologists do not fully understand DNA because there are constant changes and new discoveries developing.
 
        
                    
             
        
        
        
Answer:
The cardio-respiratory system works together to get oxygen to the working muscles and remove carbon dioxide from the body. During exercise the muscles need more oxygen in order to contract and they produce more carbon dioxide as a waste product.
Explanation: