Which molecule is most responsible for the adverse effects of pollution and deforestation on Earth's climate?
A. hydrogen gas
B. carbon dioxide
C. iron oxide
D. ammonia

B, carbon dioxide

Explanation:

It is released through many human activities such as burning fossil fuels, deforestation, land use, and even respiration.

The average atomic mass of iron is the sum of the products of the percentage abundance and masses of the isotopes. That is,
         average atomic mass = 0.0582 x 53.940 amu + 0.9166 x 55.935 amu + 0.0219 x 56.935 amu + 0.0033 x 57.933 amu = 55.847 amu
Thus, the average atomic mass of iron is approximately 55.847 amu.