Answer:
4 - 1 - 3 - 2
Explanation:
4 - Hydrogen enters the plant as part of water.
1 - Water is broken down into oxygen and hydrogen.
3 - Hydrogen combines with carbon dioxide to form glucose.
2 - Glucose is broken down to be used by plants.
During the process of photosynthesis, water and carbondioxide combined in the presence of sunlight to give rise to glucose which is then broken down to be used by plants. This is the process by which plants manufacture their food. Water is made up of hydrogen and oxygen. The hydrogen combines with CO2 to produce sugar for the plants.