<span>The high surface tension helps the paper clip - with muchhigher density - float on the water. The property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of its molecules.</span>
        
                    
             
        
        
        
Answer:
Option D, a test for the presence of cells that contain DNA
Explanation:
As we know all living organisms are made up of cells and DNA is the basic genetic material that codes for protein and traits with an organism. If even a single cell with DNA is detected on the extraterrestrial planet then it will be clear that it has life on it or the environmental conditions are favorable to support life. Cells are microscopic and hence can be seen through microscope which can be installed easily on a probe. 
Hence, option D is correct
 
        
             
        
        
        
The 3 main regions of the brain are the cerebrum, cerebellum, brainstem.
 
        
             
        
        
        
Im just guessing so i think its a