Both the terms "living" and "biotic" describe an organism that holds life. However, an organisms stops "living" after it dies, but never stops being "biotic". This is because "biotic" means anything that has ever had life, whereas "living" only describes things currently alive.
        
             
        
        
        
Xylem tissue makes up a root organ
        
             
        
        
        
Fos·sil<span>ˈfäsəl/</span>nounthe remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock. 
 so B
        
                    
             
        
        
        
Answer:
Charles Darwin and Alfred Russel Wallace