A dam is a structure built across a stream or river to hold water back. Dams can be used to store water, control flooding, and generate electricity.
        
                    
             
        
        
        
Answer: 1/4 AA or type A Blood; 1/4 BB or type B Blood; 1/2 AB
 
        
             
        
        
        
Plants and algae are the two groups of organisms 
        
                    
             
        
        
        
Frogs are insectivores. If the frogs prey on the gnats and their numbers are decreased, this allows the gnats to proliferate because the competition for survival is lessened. Gnats, being lower on the food chain, have adapted to lay large numbers of eggs due to the environmental pressures under which they evolved (being eaten in large quantities). Therefore, fewer gnats being eaten = more gnats surviving.