A cell wall known as cellouse.
 
        
             
        
        
        
Answer:
From this it can be deduced that the fresh water is hypotonic and the salt solution is hypertonic to the cells of the celery stalks. 
Explanation:
When submerged in water, the celery stalks become stiff and hard, this shows that water moves within the stalk, thus, water is hypotonic in comparison to the celery stalk. Therefore, water moves from the region of higher concentration to the region of lower concentration.  
When the same celery stalk is administered into the 0.15 M solution it turns soft, which shows that water from the celery stalk moves out. Thus, the salt solution is hypertonic in comparison to the celery stalk. Therefore, freshwater is hypertonic and the solution of salt is hypertonic to the celery stalk cells.  
 
        
             
        
        
        
<span>The gas which was not prevalent in Earth’s atmosphere during the Hadean Eon is CO2. If you are going to see the composition of the Earth's atmosphere, Carbon Dioxide has the least percentage.
</span>This is because after the hydrogen and helium had escaped, Earth's Hadean atmosphere was left with methane, ammonia, water vapor, and small percentages of nitrogen and carbon dioxide. 
See attached file for further information about the Earth's atmosphere during the Haedan Period.
 
        
                    
             
        
        
        
They walk on all fours , they can’t swim , shorter lifespan, extra chromosomes