Chapter 5, Problem 5RA

Which of these statements about the oxygen in the air we breathe is true?

$\begin{array}{l}\text{a}\text{. It functions as the final electron acceptor of the electron-transport chain}\text{.}\\ \text{b}\text{. It combines with hydrogen to form water}\text{.}\\ \text{c}{\text{. It combines with carbon to form CO}}_{\text{2}}\text{.}\\ \text{d}\text{. Both }a\text{ and }b\text{ are true}\text{.}\\ \text{e}\text{. Both }a\text{ and }c\text{ are true}\text{.}\end{array}$