A ph higher than 7 is basic so you can eliminate a. The indicator can be used to measure both acids and bases so you can eliminate c. Hydrogen ions are from acids, so the answer is that the powder decreased the hydrogen ions in the water.
The Mantle lies underneath the crust.
Given :
The ball of a ballpoint pen is 0.5 mm in diameter and has an ASTM grain size of 12.
To Find :
How many grains are there in the ball?
Solution :
Volume of ball of the ballpoint is :

Now, grain size of 12 has about 520000 grains/mm³.
Therefore, number of grains are :

In order to convert the ft^2 to m^2, we use the multiplier 0.09290304.
Therefore your calculation would be: 0.09290304 · 1930 = 179.303m^2 (rounded to 3 d.p)