Answer:
A blue moon is an additional full moon that appears in a subdivision of a year: either the third of four full moons in a season, or a second full moon in a month of the common calendar
Explanation:
The Moon can turn blue when there’s a certain amount of dust or pollution in the air. The extra dust scatters blue light, making the Moon appear more blue. 
 
        
             
        
        
        
Answer:
The villi in the small intestine provide a large surface area with an extensive network of blood capillaries. This makes the villi well adapted to absorb the products of digestion by diffusion and active transport.
Explanation:
 
        
             
        
        
        
Guard cells use osmotic pressure to open and close stomata, allowing plants to regulate the amount of water and solutes within them. In order for plants to produce energy and maintain cellular function, their cells undergo the highly intricate process of photosynthesis
        
                    
             
        
        
        
When charged particles from the sun strike atoms in earth's atmosphere, it causes electrons to move to a higher energy state. When the electrons drop back to a low energy state they release light photons. This is what causes the Aurora lights