The answer is Carbon. Beyond being the only element listed here that is located in the second row, it is also in the fourteenth column of the table if you count from left to right. Hope this helps!
Atomic mass = number of protons + number of neutrons = 4+5 = 9 amu
Answer: The yellow layer is definitely older than the red layer
Explanation: According to Nicolaus Steno's law of superposition and original horizontality. Older rocks underlie younger rocks.
Sedimentary rocks are usually deposited in horizontal layers in which each stratigraphic layer is laid down before another can be deposited upon it.
The red layer, in addition to being older, is also likely to have undergone intense oxidation due to earlier exposure.