Discover Questions

Why does the body need internal systems why can't it be just a holographic projection of light? Im having trouble on these last 2 biology questions I have. Any help would be great. Thank You.? What are the laws of probability? The function f is f(x)= (x+4)(x-a), the graph of f is a parabola , a is const. The x coord. is b/w 1 and 3, which is a?
A. -2
B. 1
C. 5
D. 9? How and when did we figure out for certain that the Earth is round?