Answer:
The first one is B and the second one is A
Explanation:
The balanced reaction between Hydrogen and Oxygen to form Water:
2H₂ + O₂ → 2H₂O
From the equation it already states that:
2 molecules of Hydrogen H₂ are needed to produce 2 molecules of Water H₂O
So the answer is 2.
Option B.
I would say that descriptive investigations aren't repeatable because it means that you are only describing something - you ask certain question about something, but do not form a hypothesis at that point yet. So it would be a waste of time to simply ask the same questions over and over again with no hypothesis to prove, which is why these types of investigations cannot be repeated.
Erica is likely to use reverse osmosis process.it is the method used in the industry to treat water in oil and gas industry .or ultra filtration method is also employed