Answer:
Crop rotation is the method of growing a series of different types of crops in the same area across a sequence of growing seasons (China does this). It reduces dependence on just one type of nutrients, it also helps control pests and weeds by the plants developing a resistance all at once.
 
        
                    
             
        
        
        
Each human cell contains 46 chromosomes.
        
                    
             
        
        
        
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. 
        
             
        
        
        
Answer: A. 
Explanation:
Palisade mesophyll cells contain the most amount of chloroplasts with an average of 30–70 chloroplasts per cell so they will be number 2 in the graph. 
Spongy mesophyll cells contain less chloroplasts than their palisade counterparts to enable them have a larger surface area for gas diffusion. 
The guard cells have the least amount of chloroplasts on average and so will be number 1. on the graph.