The simple view of the bonding in methane You will be familiar with drawing methane using dots and crosses diagrams, but it is worth looking at its structure a bit more closely. There is a serious mis-match between this structure and the modern electronic structure of carbon, 1s 2 2s 2 2p x 1 2p y 1.
Lack of sun exposure: Lack of sun exposure is a major cause of low vitamin d level especially if you live in the northern us. Less likely would be lack of vitamin d in food, but also a possibility if you are on a very restrictive diet.
This led me to wonder how common this is throughout the world and what kinds of symptoms might clue you in to the fact that you're low on vitamin D. I spoke to doctors, dietitians, wellness experts, and fellow sufferers of low vitamin D to find out what really happens when your levels are low.