While it's true that Fossils hardly even contain DNA, they can still provide numerous clues in order to identify and verify an organism.
For example, in terms of Dinosaurs, their bones and fossils have provided enough evidence to provide an evolutionary link with modern birds.
Carbon dating is another way to find the age of a fossil which provides more information on it's surrounding habitat and the animals it interacted with.
        
             
        
        
        
Phenotypic variations in genetically identical organisms that grow in the same controlled environment may be due to mutation.
<h3>Mutation</h3>
This refers to a sudden change to the DNA sequence of living organisms.
When the DNA base sequence of organisms changes, the effect is shown in the morphology of organisms. 
For organisms that are genetically identical but grow in different environments, phenotypic variations might exist as a result of environmentally acquired traits during the struggle to adapt to their environments.
In the same environment, however, genetically identical organisms are not expected to be phenotypically different, unless a mutation to the DNA of one has occurred.
More on mutation can be found here: brainly.com/question/17106056
 
        
             
        
        
        
Answer/Explanation:
Using solar energy, photosynthesis uses carbon dioxide and water to produce glucose and oxygen, whereas respiration uses glucose and oxygen to produce energy, releasing carbon dioxide and water.
Therefore, photosynthesis and respiration act as a cycle, using reverse reactants and products. 
Photosynthesis builds food for the cell to use, respiration uses this food to power cellular processes.