Vitamin B6, B12, folate, choline

Vitamin B6, B12, folate, choline
please answer the following questions in 300 words each:

1. What is the significance of each of your four vitamins? What roles do they play in the body? What bodily systems are affected?
2. What is the RDA level for each of the vitamins? What is the upper limit for each of the vitamins? What are the signs or symptoms of deficiency and toxicity for each of the vitamins?
3. Where are these vitamins found in the diet and what may impede availability and absorption? How does the concept of food poverty impact a client’s ability to obtain these vitamins?