B. To explain how things work
        
                    
             
        
        
        
The part of the leaf that is connected to the transport sister in the veins of the leaf.
        
             
        
        
        
Answer:
A cell carries out all the processes of the body which includes producing energy and storing it, making proteins which are molecules which have roles in metabolism, transportation of other molecules and DNA replication.
 
        
             
        
        
        
The correct option is A.
The serosa refers to the outermost layer of loose connective tissues which is often covered by mucus and which contains blood vessels. In the gastrol intestinal tract, the serosa refers to the outermost layer of the wall of the GI tract. One major function of serosa is to reduce friction from muscle movement.