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.
Symptoms of Low Vitamin D Levels. Vitamin D, also known as the sunshine vitamin, is one of the vital ingredients in a daily diet. If not taken in specified amounts, it can cause various health and beauty problems for an individual. This vitamin is primarily received through direct exposure to sunlight or artificial sources with ultraviolet B light.