Option 1 is correct. In photosynthesis by green plants, carbon dioxide is used for making carbohydrates. During photosynthesis, plants convert carbon dioxide and water into glucose, a type of carbohydrate, using energy from sunlight. This process takes place in the chloroplasts of plant cells, specifically in the chlorophyll-containing organelles called thylakoids. The glucose produced by photosynthesis is used by plants as a source of energy for growth and other metabolic activities. Additionally, excess glucose is stored in the form of starch, which can be broken down to release energy when needed. Therefore, option 1 accurately describes the role of carbon dioxide in photosynthesis and the production of carbohydrates in green plants.

Option 2 is incorrect. During photosynthesis, plants release oxygen as a byproduct, not use it for making carbohydrates.

Option 3 is incorrect. The carbohydrate generated by plants comes from carbon dioxide, not from the soil. While plants do require certain nutrients from the soil for overall growth and development, carbohydrates are synthesized from carbon dioxide in the air.

Option 4 is incorrect. The carbohydrate generated by plants does not come from urea. Urea is a waste product produced in animals and some plants, and it does not play a role in the synthesis of carbohydrates