The answer is D.rainforest. it is a very complex ecosystem with variety of plants and animals.
        
                    
             
        
        
        
It's called t<span>he trachea.</span>
        
             
        
        
        
Answer:
D. All cells must be reproduced by another cell.
Explanation:
The cell theory has a couple key components, which are as follows: 
#1. Cells are the basic unit of life.
#2. Cells have hereditary data that is passed down to their offspring.
#3. All cells come from preexisting cells.
#4. All organisms, both unicellular and multicellular, are made of one or more cells.
#5. Energy flows through cells.
#6. All cells have a similar composition.