The correct option is B.
Vitamin B12 are a set of water soluble related substances, which are very important for the proper functioning of some body enzymes and they are usually found together in the same food. Foods that are rich in Vitamin B12 include:meat, fish, poultry, egg and dairy. Some people who are vegetarians and who do not eat these kind of food will benefit greatly from taking vitamin B12 supplement.
Answer:
The correct answer is 2. Usually multiple mutations are required in different genes to cause cancer.
Explanation:
Mutation is the change in the DNA sequence of a cell which plays an important role in causing cancer. Mutation in many different genes allows the cell to grow and multiply in an uncontrollable manner. It also allows the cell to gain the property of metastasis.
Metastasis is the property of malignant tumor cell which allow the mutated cells to invade different tissues and organs and multiply in numbers. This property plays an important role in causing cancer. Therefore several mutations in different genes are required to cause cancer. So the correct answer is 2.
