The answer to your question is "Participant Observation".
Answer:
A. Hydrogen cans oxygen are reactants
Explanation:
Oxygen has a charge of -2. Hydrogen has a charge of +1. So it takes two hydrogens to balange the one oxygen hence the H20. So the reaction is balanced, and H20 is indeed made up of 1 oxygen and 2 hydrogen atoms. The equation 2 hydrogen + 1 oxygen (<---reactants) = Water (<--product) So hence Hydrogen cans oxygen is not a true statement. If cans is a misspelling then C would be your answer.
Hope that helped
Answer:
a)
b)
hours
Explanation:
Given
Surface Area (S) of 250 grams of powder sample 
square meter.
square centimeter
grams/minute
mg per second
gram per cubic meter 
mg/ml
a)
cm /sec
b) Time taken
Time taken to sink
Time in hours
hours
Magnesium salt is the type of substance
