Answer: Pulmonary aortic valve
Explanation:
 
        
             
        
        
        
The answer is B. They are both made up of subatomic particles.
        
                    
             
        
        
        
Answer:
Osmosis is the movement of molecules from a region of lower concentration to a region of higher concentration through a semi-permeable membrane
 WHILST
Diffusion is the movement of molecules from a region of higher concentration to a region of lower concentration until the molecules are evenly distributed
 
        
                    
             
        
        
        
1) Chloroplast 
 -converts solar energy into food for the plant. 
2) Cell Wall 
 -provides protection and structure.
        
             
        
        
        
Answer:
Walking
Explanation:
A muscle cell usually contracts or expands simultaneously when one is working or doing some activities like running, exercises, house chores e.t.c
Muscles are flexible fibers that are very essential appendages for locomotion in human beings. 
For muscle cells to contract, they are pulled together thereby causing tension in the muscle. When they are relaxed, they move away from one another.