Biological species is the term for a group of interbreeding organisms that are able to produce fertile young. 
        
             
        
        
        
Answer:
The correct answer is - passive immunity - artificially acquired.
Explanation:
Passive immunity is the immunity that involves giving or acquiring antibodies from other sources instead of developing them on one's own. This type of immunity can be natural and artificial. Mother breastfeed the babies, is the natural passive immunity example as milk also contain antibodies required for immunity of babies.
Artificial passive immunity is the immunity that comes from injecting the antibodies created in different animals or persons which called antiserum or vaccines such as snake antivenom.
 
        
             
        
        
        
Answer:
Perform different functions for the organisms
Explanation:
1-Stem cells can differentiate into other specialized cells.
2-Specialized cells are more complex. 
3-Specialized cells usually do not reproduce
 
        
             
        
        
        
Answer:
Proteins can carry nutrients across the plasma membrane. There are also differnet receptros outside the cell that recieve signals as well as inside the cell. 
Explanation:
 
        
             
        
        
        
Lemon juice is 10,000 more acidic than urine