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.
Vitamin D. Why you need it: Vitamin D is crucial for bone health and calcium absorption. Vitamin D deficiency also has been linked to certain cancers and heart disease. But unlike other vitamins, our main source of vitamin D is not food â itâs the sun. So risk factors for low levels include living at high latitudes, high levels of air pollution or city smog, dense cloud covering, a high degree of clothing covering the skin, increased sunscreen use and darker skin pigmentation.