Answer:
c.is the answer..not sure...but i think so
Answer:
A. An indicator added to the solution turns green-blue.
Explanation:
A pH scale measures the concentration of hydrogen ions in acidic and alkaline solutions.
In chemistry, pH literally means the power of hydrogen ions and it is a measure of the molar concentration of hydrogen ions in a particular solution; thus, specifying the acidity, neutrality or basicity of any chemical solution.
Mathematically, the pH of a solution is given by the formula;

On a pH scale, a solution with a pH of 7 is neutral, a solution with a pH below 7 is acidic and it's basic (alkaline) when it's pH is above 7.
A pH indicator can be defined as a compound (substance) that indicates the concentration of hydrogen ions present in a solution by changing its color over a narrow range of pH values.
A pH range of 1 to 3 (1 - 3) represents a strong acid with a red color.
When an indicator added to a solution turns green-blue, it simply means that a weak base is present.
Answer:
Explanation:
Given parameters:
Number of breathe per minute = 15times
Volume of air per breath = 0.5L
Percentage of oxygen in air = 21%
Solution
There are 24 hours in a day.
60minutes makes a hour in a day,
I will breathe:
15 times x 60 x 24 = 21600 times in a day
The volume of air I will take in per day:
A breathe = 0.5L of air
21600breathe = 0.5 x 21600 = 10800L of air
Volume of oxygen I will breathe per day:
x 10800 = 2268L of oxygen
Answer: ( Outwash )
hope this helps!