The correct answer is A I believe
        
             
        
        
        
Answer:
Here's what I get  
Explanation:
CH₃CH₂CH₂CH₂CH₂CH₃ —  hexane
CH₂=CHCH₂CH₂CH₂CH₃ —  hex-1-ene is the preferred IUPAC name (PIN). 1-Hexene is accepted
CH₃C≡CCH₃ —  but-2-yne (PIN); 2-butyne is accepted
CH₃CH(CH₃)CH₂CH₂CH₃ — 2-methylpentane
CH₃CH₂CHCICH₂CH₃ — 3-chloropentane
 
        
                    
             
        
        
        
Groundwater is also one of our most important sources of water for irrigation from septic tanks and toxic chemicals from underground storage tanks and leaky landfills ... Drinking contaminated groundwater can have serious health effects. If there is a leak, these contaminants can eventually make their way down
  
        
             
        
        
        
False, Atoms are the smallest units of matter that display both the chemical and physical properties of it, based on the structure of the atom.