Hot temperatures, natural disasters, agriculture, urbanization, etc. 
Mark me as brainliesttttt !!
        
             
        
        
        
Its the  Eccentricity of the earth. (shape of Earth's Orbit around the sun, whether it is more circular or ovular.)
        
             
        
        
        
A) One species always outcompetes the other until only one species remains.
        
             
        
        
        
An independent variable is something a Scientist messes with like baking soda and vinegar the independent variable is the baking soda and vinegar and the dependant variable is the explosion