Biology QuizTheLastDialogue BIOLOGY QUIZ Test Your Knowledge Of Biology With These Quizzes Biology Online Quiz for Kids and Adults #1. How many neurons are there in an average human brain? One billion One billion 100 Trillion 100 Trillion 100 billion 100 billion 1000 million 1000 million Work Harder #2. Is there a central processing Unit in the brain? Yes Yes No No Work Harder Finish Results Well Done. You Are Roaring Like A Lion Keep Working. Slow & Steady Wins The Race START NEW