I only know 2 and 3 are correct. I’m not sure about the last one.
The best way to do a observation can be a microscope or by taking notes ,and by , taking pictures or, asking questions about the subject that you and the teacher or you, your teacher and the class is talking about .! Hope this helps ..
Answer:
answer is carbon dioxide its correct
Answer:
Either A or C but A is a bit more true
Explanation:
You can measure one on option C but you can measure both
on answer A. Hope this helps you out.