Humanists believe that

A. humans and animals existed on the same level.

B. Shakespeare didn't actually write the plays we think he did.

C. love is an illusion.

D. life on earth is important in its own right.

The correct answer for this question is D - humanists believe that life on earth is important in its own right. The humanist philosophy is that human beings have control over their own lives, and humanists generally reject religious or superstitious ideas in favour of logical thinking.