The answer is guard cells. 
Guard cells are cells surrounding each stoma. They help regulate the rate of transpiration by opening and closing the stomata. They are specialized cells in the epidermis of leaves, stems and other organs that are used to control gas exchange. They are produced in pairs with a gap between them that forms a stomatal pore (stoma).
        
                    
             
        
        
        
1) Independent Variable- I change: the lighting or the dark vs light (Idk if I'm making sense)
Dependent Variable- data being collected: How many ants end up on either side
Hypothesis- If, then statement... Well you can make this up but if you need my help I'll help... Hope this helpsss!!
        
             
        
        
        
If DNA is found at a crime scene it can help locate people that were at the crime scene. If the criminal has committed crimes before their DNA will already be in the police system. If not they can take samples from suspects and pinpoint who committed the crime.
        
                    
             
        
        
        
Ontonic Pressure, or colloid osmotic pressure, is a form of osmotic pressure exerted by proteins, notably albumin, in a blood vessel's plasma (blood/liquid) that usually tends to pull water into the circulatory system. It is the opposing force to hydrostatic pressure.
Hope this helps! <3