DENDROLOGY

Detailed explanation-1: -Plants, like animals, take in oxygen and give out carbon dioxide during respiration. Only during photosynthesis, plants take in carbon dioxide and release oxygen as a byproduct.

Detailed explanation-2: -Plants use photosynthesis to capture carbon dioxide and then release half of it into the atmosphere through respiration. Plants also release oxygen into the atmosphere through photosynthesis.

Detailed explanation-3: -Complete step by step answer: Oxygen is not essential for the process of photosynthesis because oxygen is released in this process when plants utilize the raw materials i.e., carbon dioxide and water to produce sugars (glucose). Hence, it is not essential to carry out the process of photosynthesis.

Detailed explanation-4: -Once they have water and carbon dioxide, they can use energy from sunlight to make their food. The leftovers from making the plant food is another gas called oxygen. This oxygen is released from the leaves into the air.