Freezing
boiling
Vitamin D
magnesium, vitamin A, and Vitamin D
vitamin a Any fat-soluble vitamin.
adults
It's likely that grains do have vitamin B. Some grains have 26% of vitamin B, some grains have 15% of vitamin B etc.
People with a diet of regular and adequate intake of foods rich in vitamin A; or taking vitamin A supplements.
d
Simple, Eat Meat. This is the reasons why vegetarians are much more likely to get vitamin B12 deficiency.
Most likely at your local vitamin shop.
vitamin a
The likely word is "vitamin" (necessary metabolic compound).