Answer:
Photosynthesis
Explanation:
In order to make foods (carbohydrates) plants make photosynthesis to convert H20+CO2 to C6H12O6(simple form of sugar,monosccharide(carbohydrate)) it uses sunlight. In this ecosystem grass and the trees are creating the carbohydrates.
Joint - a joint is where two bones articulate
In this case, the femur and tibia form a joint.