What enzyme is kept in its active form by the presence of vitamin c in the diet? is prolyl hydroxylase the active form enzyme here?

yes, Porlyl Hydroxylase

Enzyme productions also depend on the supply of iron and it is crucial in the total development of children who are growing and developing hormones, neurotransmitters, and new cells within their body. If iron stores are low, memory, mood, attention span, and focus are among the effects of the deficiency because oxygen transport in the blood is lessened or diminished. 

The short-term effect of tar on the body is increased blood pressure.