In the following passages, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.
PassageTap to readHide
Photosynthesis is the _______ (635) used by plants, algae and some bacteria to turn sunlight into energy. The process chemically ________ (636) carbon dioxide and water into food and oxygen. The chemical reaction often _______ (637) on a pigment called chlorophyll, which gives plants their green colour. Photosynthesis is also the _______ (638) our planet is blanketed in an oxygen-rich atmosphere. Plants absorb carbon dioxide from the ______ (639) air and release water and oxygen via microscopic pores on their leaves called stomata.
Select the most appropriate option to fill in blank number 638.
Show answerAnswer & explanation
Correct option: C — reason
Reason ‘Reason’ means a cause or explanation for something. The given passage states that photosynthesis is also the reason for our planet having an oxygen-rich atmosphere. Hence, ‘reason’ is the most appropriate answer.
