Elevation can affect the amount of sunlight that plants receive, the amount of water that plants can absorb and the nutrients that are available in the soil. As a result, certain plants grow very well in high elevations, whereas others can only grow in middle or lower elevations.
        
                    
             
        
        
        
Cellular Respiration is the making of energy in the mitochondria. Photosynthesis is the production of oxygen in the chloroplasts. Their reactants are the products of each other. 
 
        
             
        
        
        
Answer:
The correct answer is - regulation of the heavy metal and their toxicity.
Explanation:
Metallothionein is a group of cysteine-rich, small in size, and highly conserved proteins that bind to various metal ions and regulate their activity or toxicity in transcriptional level.
Metallothionein IIA is one of the metallothioneins that binds to heavy metal and helps cells to be protected from the toxicity of these heavy metals. These proteins are present in almost every eukaryotic organisms virtually. These proteins are highly induced to express highly in the present of heavy metals.
Thus, the correct answer is - regulation of the heavy metal and their toxicity.