The majority of the matter that makes up a plant comes from the air and water. Through the process of photosynthesis, plants use sunlight to convert carbon dioxide from the air and water from the soil into glucose, which is used as an energy source for the plant. This process also produces oxygen, which is released into the atmosphere. In addition to carbon dioxide and water, plants also absorb other nutrients, such as nitrogen, phosphorus, and potassium, from the soil. These nutrients are essential for the plant's growth and development.