The answer to this question is B
Three weeks is how long a human can live without food
A stands out most to me, CO comes from the air and air is basically oxygen we breath. When we exhale CO comes out (of course). I would say A is correct.
The valence electrons of carbon are important because the valence give an element their bonding properties. If Carbon did not have as many, it would not be able to bond four times. or have many of the properties it possess.
