I’m not 100% sure if this is a scientific theory but I’m going with the big bang theory. The big bang theory is a scientist best guess on how the world came to be. A 2013 map of the background radiation left over from the Big Bang, taken by the ESA's Planck spacecraft, captured the oldest light in the universe. This information helps astronomers determine the age of the universe.
        
             
        
        
        
If a mutation results in an organism with new characteristics then eventually a new species will be formed if more such mutations will continue to accumulate in the individual. Mutations result into the accumulation of variations in an individual and when such variations keep on accumulating in a particular organism consistently it leads to formation of a new species or we can say that evolution has occured.
 
        
             
        
        
        
Answer:
A mature animal will  have been fully developed whereas an immature animal will not be fully developed. In a mature animal, all stages of development will have occurred whereas in an immature animal not all developmental stages would have occurred.
A mature animal will be better adapted to live in an environment as compared to an immature animal. 
 
        
             
        
        
        
Answer:
All of these examples show evidence for evolution because they show change over time and descent from a common ancestor
 
        
                    
             
        
        
        
Water temperature and pressure determine how far sound travels in the ocean. ... The whale produces sound waves that move like ripples in the water. As the whale's sound waves travel through the water, their speed decreases with increasing depth (as the temperature drops), causing the sound waves to refract downward.