Ontario Grade 9 Science Class Practice Exam

Plants utilize nitrates by absorbing them into their roots. Option A is incorrect because plants do not convert nitrates into nitrogen gas, rather they absorb nitrates and use them to build proteins and DNA. Option C is also incorrect because plants do not break down nitrates into ammonium, rather they use nitrates as an important source of nitrogen for their growth. Option D is incorrect because plants do not emit nitrates into the atmosphere, rather they use them to support their growth and metabolism.