Answer:
Niacin (Ans. A)
Explanation:
Nicotinamide adenine dinucleotide (NAD) is known as important cofactor which help in carrying electrons from one reaction to another reaction in the cellular respiration process.
Cells are able to restore performed compounds which are containing a pyrimidine base precursor vitamin for the synthesis of NAD: nicotinamide, nicotinic acid, and nicotinamide riboside. 
These elements are taken up from the diet whos containing vitamin B3. Nicotinamide, and nicotinamide riboside both can be absorbed from the gut. Niacin or vitamin B3 also produced within cells with the help of cellular digestion of NAD+.
 
        
             
        
        
        
Answer:
the soil matter formed by decade organic matter is called humus.
 
        
                    
             
        
        
        
It all depends on what kind of liquid it is, if you were to use water, the plant would be fine, but if you were to give it, say, car gas, the plant would most likely die..... I hope this helped!
        
             
        
        
        
Answer:
Explanation:
It is called a double circulatory system because blood passes through the heart twice per circuit. The right pump sends deoxygenated blood to the lungs where it becomes oxygenated and returns back to the heart. The left pump sends the newly oxygenated blood around the body.
 
        
             
        
        
        
I think 1 is C and 2 is A