Species are single organisms that are able to reproduce, while a population is a group of species living in the same general area.
        
             
        
        
        
Answer: Gastrocholic reflex
Explanation:
The gastrocholic reflex or gastrocolic response is one of the physiological reflexes in the stomach  which controls the movements like peristalsis and motility in the gastrointestinal tract.
This reflex is generated by the the food particles that enters the stomach. The  bolus of the food in the stomach helps in the mass movement of the other food particles in the colon.
This reflex is known as gastrocholic reflex.
 
        
             
        
        
        
Answer:
Intelligent Design
Some scientists who are Christians have developed a theory called Intelligent Design to explain the creation and development of life on earth.
However, in my opinion its complete nonsense 
 
        
             
        
        
        
Answer: I'm pretty sure it's the first one
Explanation: I don't know for sure but I'm pretty sure when I learned it they said that extrusive is above ground and intrusive is below ground. Don't take my word for 100% though