It’s due to stem cells. The genes in dna turn on and off to give a cell a specific job, so stem cells can be “programmed” as any cell the body needs. (Muscle cell, skin cell, etc)
        
             
        
        
        
Both dolphins and whales still have their hip (pelvic) bones present. These bones connect and transfer the weight of the trunk to the lower limbs.
Thus, <em>the presence of the pelvic bone may indicate that whales had ancestors that walked on land</em>. 
 
        
                    
             
        
        
        
Answer:
B
Explanation:
in photosynthesis CO2 is used to produce glucose NOT energy.
in cellular respiration O2 is used to produce energy NOT CO2.
in cellular respiration oxygen is used to produce energy and CO2.
 
        
             
        
        
        
A - Viruses cannot survive outside of a host whereas bacteria can.