Answer:
color of light
Explanation:
<em>The independent variable is the variable that is supplied and often varied/manipulated by the researcher during the course of experiments. It is varied/manipulated in order to see the effect it will produce on another experimental variable - the dependent variable.</em>
In this case, out of all the variables supplied by Mary, only the color of light supplied was varied - red, white, green, and blue; other variables supplied were kept constant. Hence, <u>the independent variable is the color of light.</u> 
 
        
             
        
        
        
Answer:
A/D
Explanation:
D, Fertilizers put more sulfur in the ground than their should be.
 A, fossil fuels, could also be the answer. When we combust fossil fuels we release the sulfur in them into the atmosphere when they should not be in the air.
 
        
             
        
        
        
Answer:
humans and chimpanzees share a relatively recent common ancestor
Explanation:
someone else has asked the same question
 
        
             
        
        
        
Pretty sure its Ph scale i did a question like this once but i cant remember....its either Ph or richer