Answer:
element
Explanation:
elements consist of pure substances
Radon is <span>not a source of air pollution related to human activities</span>
Answer:
3.4 × 10
^−
4
Explanation:
Move the decimal so there is one non-zero digit to the left of the decimal point. The number of decimal places you move will be the exponent on the
10
. If the decimal is being moved to the right, the exponent will be negative. If the decimal is being moved to the left, the exponent will be positive.
