The oxygen cycle is extremely complicated and is summarized only briefly here. Oxygen occurs in many chemical forms and is released into the atmosphere in a variety of ways. Most of the oxygen in the atmosphere is molecular oxygen produced when plants decompose water molecules in photosynthesis. Some atmospheric oxygen is bound up in water molecules that came from evaporation or plant transpiration, and some is bound up in the carbon dioxide released during animal respiration. Much of this carbon dioxide and water is eventually recycled through the biosphere via photosynthesis.
The purpose of the paragraph is
a. to inform the reader of the complexity of the oxygen cycle.
b. to describe how photosynthesis takes place.
c. to compare the chemical forms in which oxygen occurs.
The tone of the paragraph is
a. judgmental. b. informative. c. analytical.
Question 2
Your purpose for reading, the difficulty of the material, and your reading ability should determine how fast you read.
Indicate whether the statement is true or false
The Atmosphere’s Oxygen Came from PhotosyntheticOrganisms
The menstrual cycle.
A difference in oxygen content between the atmosphere and the exhaust gases enables an O2S to ...
The Krebs–Henseleit urea cycle
The phosphorus cycle "دورة الفوسفور"
Exchange of Oxygen and Carbon Dioxide