Answer:
gravity
Explanation:
Gravity from Latin gravitas meaning weight for gravitation is a natural phenomenon by which all things with mass or energy including planets stars or galaxies and even light are brought toward or gravitate toward one another gravity gives way to physical objects 
 
        
             
        
        
        
Our food is our energy. When we eat food, we need to digest it and the eaten food, once digested, serves as our energy that we use up for daily needs. If we eat too much food, it will be store and we will become overweight over time. If we don't eat enough, we will lose weight because we're not getting enough energy in our bodies, so our bodies cannot get enough energy from the food eaten, so it looks elsewhere for stored energy - our fat and muscle cells. 
        
             
        
        
        
Mitosis is the correct answer 
Mitosis makes exact copies of DNA whereas in Meiosis it creates all different kinds of cells to create the organism
        
                    
             
        
        
        
Answer: Respiratory gases(Oxygen)
Explanation:
The essential role of cadio vascular system is to supply blood; containig metabolites (glucose,amino acid, fatty acid and glycerol) and gases expecially Oxygen,needed for combustion of these nutrients(metabolites) in mitochondrial of cells (cellular Respiration) to generate ATPs for biochemical activities of the body.