The vestibular sense tells you whether you are physically upright without using your eyes

Which statistic accurately reflects the vulnerability of prenatal development?

Only 31 percent of all conceptions become living newborn babies. Only 75 percent of fetuses reach the age of viability. 50 percent of fetuses are spontaneously aborted or stillborn. 10 percent of all fetuses die during birth.

A scientific theory has to be

a. true. b. accepted by others. c. testable. d. well established and not disputed.