That is a chemical change or reaction.
        
                    
             
        
        
        
Regular human body cells or somatic cells have a total of 46 chromosomes. Therefore, because of meiosis, sperm cells, which are gametes or sex cells must contain 1/2 of the number of total chromosomes found within a somatic cell, to make sure that the chromosome number within an organism is maintained, this would be 23 in this case.
        
             
        
        
        
The convergent boundary or just convergent
        
             
        
        
        
Answer:
 (4) tissues
Explanation:
There are three circles the innermost circle indicated the cells middle circle is the tissues and the outermost circle indicated the organs. Multicellular organisms are made up of thousands of different types of cells .Different cells constitute together forma a tissues and different tissues form a organ and different organs together form an organ system. Hence the X labeled circle denotes the tissues.