C it will be c because earth has water 
 
        
                    
             
        
        
        
Past climate changes led to extinction of many species, population migrations, and pronounced changes in the land surface and ocean circulation. The speed of the current climate change is faster than most of the past events, making it more difficult for human societies and the natural world to adapt.
        
             
        
        
        
A molecule is a group of two or more atoms held together by chemical bonds. A compound is a substance which is formed by two or more different types of elements which are united chemically in a fixed proportion. All molecules are not compounds. All compounds are molecules.
        
                    
             
        
        
        
Biofeedback <span>is stress-reduction technique whereby electronic equipment measuring a person’s involuntary (neuromuscular and autonomic) activity helps him gain a level of voluntary control over these processes.
Biofeedback therapy will help you to relax and control involuntary response related to stress like heart rate, sweating, temperature and blood pressure. The electronic equipment will let you know when there is any sign of stress, therefore you know when to calm down yourself.</span>
        
             
        
        
        
Answer:
1)the process being studied in the picture is transpiration I guess
3)the pot is covered with plastic sheet to trap the water (vapour) which is being evaporated