1. Which of the following provides the best evidence that living things use and
recombine carbon, hydrogen, and oxygen to form molecules for new cells?
a. The elements carbon, hydrogen, and oxygen are among the most common elements in the
universe, but are not the most common elements on Earth.
b. The cells of living things contain molecules made of the elements carbon, hydrogen, and
oxygen, the same elements found in the glucose consumed by living things.
c. The elements carbon, hydrogen, and oxygen are able to bond with each other to form complex
molecules that are chains of repeating structures.
d. The relative amounts of carbon, hydrogen, and oxygen found in the earth's atmosphere have
changed over the history of the planet during which living things evolved.