Glucose is broken down during cellular respiration to produce carbon dioxide and?

Ineed to know why d is the correct answer asap

Which medullary index indicates a human hair? a. 0.653 b. 0.733 c. 0.516 d. 0.256

Which of the following is a reason why early living organisms on earth could not have survived on the surface? 1. the lack of an ozone layer 2. the lack of oxygen in the atmosphere 3. the fact that these organisms were single-celled