To photosynthesize, plants take in carbon dioxide and release oxygen, which is helpful for us because humans happen to need oxygen to breathe. But for plants, the purpose of photosynthesis isn't to release oxygen. In fact, oxygen is just a byproduct of the process. The purpose of photosynthesis is the production of a very important simple sugar called glucose. Glucose, a carbon-based molecule, is needed for cellular respiration, another biochemical process. In cellular respiration, glucose is broken down to produce ATP. ATP is like a cell's energy currency. Almost all functions in the cell take ATP, which means cells have to "spend" ATP to do other things, like grow or repair.

Question

To photosynthesize, plants take in carbon dioxide and release oxygen, which is helpful for us because humans happen to need oxygen to breathe. But for plants, the purpose of photosynthesis isn't to release oxygen. In fact, oxygen is just a byproduct of the process. The purpose of photosynthesis is the production of a very important simple sugar called glucose. Glucose, a carbon-based molecule, is needed for cellular respiration, another biochemical process. In cellular respiration, glucose is broken down to produce ATP. ATP is like a cell's energy currency. Almost all functions in the cell take ATP, which means cells have to "spend" ATP to do other things, like grow or repair.

Which detail from the passage best explains why plants photosynthesize?

A
"The purpose of photosynthesis is the production of a very important simple sugar called glucose."

B
"To photosynthesize, plants take in carbon dioxide and release oxygen, which is helpful for us because humans happen to need oxygen to breathe."

C
"In fact, oxygen is just a byproduct of the process."

D
"...cells have to 'spend' ATP to do other things…"

Answer 1

A

"The purpose of photosynthesis is the production of a very important simple sugar called glucose."