A sample of Element "X" is found to contain three isotopes. The first isotope has a mass of 1 amu and a natural abundance of 99%. The second isotope has a mass of 2 amu and an abundance of 0.80%. The third isotope has a mass of 3 amu and an abundance of 0.20%. Calculate the average atomic mass of element "X": a
1.099 amu
b
1.012 amu
c
1.118 amu
d
1.904 amu
e
0.990 amu
f
1.304 amu
g
0.9874 amu
h
1.000 amu

Why is it important for scientists to review and repeat the work of other scientists? 1.a scientific theory must be tested three times before it is proven. 2.the scientific method only applies to repeated experiments. 3.an experiment may have had errors that the scientists didn't recognize. 4.the results of individual scientists may be influenced by bias. 5.an experiment must be performed twice before the data can be analyzed.