Through cellular respiration, glucose is converted into a form of energy that cells can use. So what is glucose, and where does it come from? Glucose is a simple sugar. It is an energy-rich food molecule that contains atoms of carbon, hydrogen and oxygen. Glucose has the chemical formula C6H12O6. Animals get glucose from the food that they eat. During digestion, food particles are broken down into smaller molecules, like glucose. But plants do not eat food. Instead, they use the sun’s energy to convert carbon dioxide (CO2) and water (H2O) into glucose (C6H12O6) and oxygen (O2). This process is known as photosynthesis. The equation for photosynthesis shows that new atoms are not created during this chemical reaction. Existing atoms rearrange: 6H2O + 6CO2 + energy → C6H12O6 + 6O2.

Question

In the passage above, what is the purpose of the underlined sentence?

A
to clarify a common misunderstanding about plants

B
to further describe the qualities of plants

C
to transition to describing the way plants get glucose

D
to support the claim that not all organisms need nutrients

Answer 1

The purpose of the underlined sentence is:

C. to transition to describing the way plants get glucose

This sentence introduces the process of photosynthesis, which explains how plants produce glucose, thus serving as a transition from discussing how animals obtain glucose from food to how plants generate their own glucose.