Brittle bones and teeth.
There is more than one reason that your vitamin D is low. It could be due to lack on sunshine or poor diet.
A blood test would show if you are low in Vitamin D.
No. It, in fact, is the opposite. Vitamin D is absorbed in the intestine, converted by UV radiation in the skin, and then helps absorb Calcium into the body. Vitamin D deficiency can be caused by a few things, a diet low in Vitamin D, low sun exposure, or it could be caused by a tumor in the parathyroid gland (but if you have low Calcium, that is not possible).
Rickets
No, it can not.
With
vitamin D human skin produces vitamin D when exposed to sunlight
Orange juice fortified with vitamin D and milk fortified with vitamin D.
No, vitamin D is not from jade stone. Vitamin D is an animal product. Good food sources of vitamin D are milk, eggs, fish, beef, etc. We can also produce vitamin D in our skin when it is exposed to ultraviolet radiation (usually from the sun).
Vitamin D
The common symptoms of low vitamin D is sythnetisis to the sun light, having no energy, having pale skin and not being able to concentrate on anything.