The correct response is: This is not true because plants need to sequester nitrogen from the soil to build amino acids.
While it is true that photosynthesis allows plants to create glucose and other carbohydrates that serve as the building blocks for some biomolecules, plants cannot solely rely on photosynthesis to obtain all the elements needed for building all types of biomolecules. For instance, amino acids (the building blocks for proteins) require nitrogen, which plants must obtain from the soil. Additionally, plants also need other nutrients such as phosphorus and potassium for various biological functions. Therefore, while photosynthesis is a critical process for plants, it is not sufficient on its own for them to create all necessary biomolecules.