Answer:
conservation of natural resources
Explanation:
You're trying to save resources, all the other options cause harm
 
        
             
        
        
        
Answer:
This is a cell (B) with a nucleus (C) containing DNA (A). The DNA is organized into chromosomes (D). A section of the chromosome that codes for a trait is called a gene (E).
Explanation:
 
        
                    
             
        
        
        
No caffein,there is a factor that must not be changed when conducting an experiment,known as controlled variable
        
             
        
        
        
Answer:
Chemical bonds contain potential energy.
Explanation:
Chemical bonds always contain potential energy. The atoms of the bond want to move to a lower energy to become more stable.. The energy for breaking bonds only comes when stronger bonds are formed.  This energy is used to tear apart the bonds holding the Hydrogen atoms together. The strength of the covalent bonds depend on the overlap between the valence orbitals of the bonded Atom. 
 
        
             
        
        
        
At the end of the winter they are most numerous in fresh water. they will cover surface of aquatic plants or poles and wooden borders of ponds. If you like to study them you can scrape the brown growth with a flat piece of plastic. you can also use a sponge. for the free living (plankton) species fine mesh plankton net is very useful.