From the description of the food that the doctor is advising Natalia to start consuming, it is clear that she is suffering from (C) Vitamin D deficiency.
Someone with a vitamin D deficiency would be at risk of rickets, an illness where someone will have skeletal deformities due to soft bones. Increased risk of death due to cardiovascular disease and cancer is also associated with someone who has a vitamin D deficiency.
It introduces you to new information, which will you will need in the long run.
Because you breathe faster and in effort to quickly bother the oxygen rich blood to you body
True, if someone combines it with recreation (such as a sport), they are still getting physical activity while having fun.
