The answer is a or b or c or d hope dis helps bruddas at riverdale high school 10th grade 
        
             
        
        
        
Fossils can be found in the Earth's crust. 
The crust is the thinnest layer of the Earth. The fossils are most probably be found in this layer because it is the outermost layer. Also, the deeper the layer of the Earth, the higher the temperature that it has, and it probably cannot preserve the fossil. 
 
        
             
        
        
        
Plant trees because they absorbe co2
        
                    
             
        
        
        
Answer:
   Variations Within Ecosystems
Ecosystem diversity can be described as a term which is used o describe the changes within an ecosystem and the impact these changes have on the environment and humans. 
Variations within an ecosystem can cause genetic drifts. Variations will cause those organisms to survive which are better adapted to survive to the changes which occur in an ecosystem. And the organisms which are not better suited become extinct over a period of time. Hence, this will lead to a wide rise in biodiversity.