Answer: The answer is C. Hope this helps :)
Explanation:
I think that the answer is 12 billion. So sorry if I am not right.
(C) earth's outer iron core
this is because iron is magnetic and therefore forms a strong magnetic field
The answer is A. Decreased pH levels. A substance having a pH value less than seven is considered to be acidic. Increases in the concentration of these gases from the use of fossil fuels leads to more acid precipitation, lowering the pH of aquatic environments. Plant life and soil can also be affected by acid rain. Buildings and other infrastructure can be damaged.
Light is the energy source for plants synthesis of simple sugar in plants.
