C. marbles placed inside hollow sphere
A biomass source is an natural material.
The sun is natural.
Manure is natural.
Wood Chips are natural.
Paper is natural and treated with unnatural substances.
pH decreases as the hydrogen ion concentration increases.
<u>Explanation:</u>
When there is a decrease in pH, that is pH decreases from 6 to 3 then the acidity increases.
That is the pH is between 1 to 7 then it is acidic
When the pH is 7 then it is neutral
When the pH is between 7 to 14 then it is basic
As the H⁺ ion concentration increases, then the pH value decreases, here pH decreases from 6 to 3.
So the concentration of Hydrogen ion increases, pH decreases.
Answer:
1.25 gram of cesium-137 will remain.
Explanation:
Given data:
Half life of cesium-137 = 30 year
Mass of cesium-137 = 5.0 g
Mass remain after 60 years = ?
Solution:
Number of half lives passed = Time elapsed / half life
Number of half lives passed = 60 year / 30 year
Number of half lives passed = 2
At time zero = 5.0 g
At first half life = 5.0 g/2 = 2.5 g
At 2nd half life = 2.5 g/ 2 = 1.25 g
Thus. 1.25 gram of cesium-137 will remain.
Photosynethesis, respiration, and combustion.
