Question 3.Why is the atomic mass of carbon not a whole number as listed in the periodic table?*
O A. Because Carbon-14 is used to date fossils.
B. The most stable artificial radioisotope is carbon-11.
C. Because carbon needs 4 extra electrons to complete its valence shell.
D. Because it is the weighted average of the three naturally-occurring isotopes of
carbon

a is the answer to this question

explanation:

1. they vary with a higher number because boiling is way hotter than melting

qualitative observation deals with data that can be observed with our senses: sight, smell, touch, taste, and hearing. they do not involve measurements or numbers. for instance, colors, shapes, and textures of objects are all qualitative observations.