Hi there! Air and sunlight can definitely be reused. Those are abundant and renewable resources. Therefore, A and D are eliminated. There is a limited amount of water, however, it's impossible to run out of it to the point that there's no more on Earth. C is out. The only answer choice that makes sense is coal, because it's a nonrenewable resource, and it takes millions of years to make more of. It's a fossil fuel, so once we use them up, we can't get anymore during our lives. The answer is B: coal.
The pH scale ranges from 0 to 14 and goes from acidic to alkaline, where 7 - the center of the scale - is the most neutral.
Answer:
The pH of a neutral solution is exactly 7.
Hey there!
The elements in this equation are K, N, O, H, and C.
Let's count how many of each are on each side to see if it is balanced.
K: 2 on the left, 2 on the right.
<em>N: 2 on the left, 4 on the right. </em>
<em>O: 9 on the left, 6 on the right. </em>
<em>H: 2 on the left, 4 on the right. </em>
C: 1 on the left, 1 on the right.
Notice that there are different amounts of N, O, and H on the left side and the right side.
This means that the equation is not balanced.
Hope this helps!
The answer is A because I did this before