单项选择题 We peer out beyond our world to glimpse objects that lie at the very edge of the universe, stars teetering tantalizingly on the beginning of time. We peer inward to our own genome, swiftly unraveling the puzzle of what tiny bit of chemical code manifests themselves as appearance,tendency, advantage and liability in the marvelous human creature.（）
A.at the very edge of
B.stars teetering tantalizingly
C.what tiny bit of
D.manifests themselves as