The desert and tundra are alike because they both have limited available water. 
        
                    
             
        
        
        
Answer: The idea that the earth is extremely ancient.
Explanation:
Charles Darwin was a British naturalist who worked on the organic evolution of living organisms and in his books outlined how present-day organisms evolved from earlier, different species.
Evolution is an extremely slow process. It is difficult to obtain direct evidence of evolution in action. However, scientist including Charles Darwin, have from many fields gathered a great deal of indirect evidence that supports the theory of evolution. This evidence comes from many sources which include the FOSSIL RECORDS.
The history of life on earth is recorded in fossils (remains of organisms preserved mainly in earth's sedimentary rocks). Scientist can determine the age of rocks in which fossils occurs by using RELATIVE DATING. This method give a geological time scale, showing earth's age ( as measured by dating it's rocks), and tracing the history of life on it.
Therefore the idea that the earth is extremely ancient is associated with relative dating which has helped inspire Charles Darwin's work as an evidence on evolution.
 
        
             
        
        
        
It's a way of protecting the trees, and making sure they survive the winter and beyond. Leaves die during the winter months. If those dead leaves stayed on the trees, and new ones wouldn't grow in their place, the tree would have no way of making food for themselves. 
Hope it helps. ☺
 
        
             
        
        
        
A small town is located near a body of water and enjoys cooler temperatures than other areas in the same climate zone. This is an example of a microclimate
Explanation: 
- The microclimate is nothing but experiencing a different temperature, which is restricted to a certain area only. It might be experiencing a lower temperature in comparison with the surrounding regions. 
- The dry climate is experiencing a very high temperature and polar climate is nothing but a region where there are no warm summers and the temperature would be less than 10 degree Celsius. 
- Climate zones are characterized by distinct parameters and these are found near the poles 
 
        
             
        
        
        
Answer;
The amnion 
Explanation;
-The amnion is a tough, thin membrane that surrounds a developing fetus in mammals, reptiles, and birds. It is the first of the three cavities (amnion, chorion and yolk sac) in the embryo and is formed on 8 dpc.
-In the human body, the amnion is the first of three cavities, including the chorion and yolk sac, that work together to keep the developing fetus nourished and protected.
-The amnion provides a protective environment in which the fetus' temperature is regulated and protects the fetus from friction caused by the mother's movements.