Question

Scientists have known for a long time that vitamin D is essential for
humans. If children have a vitamin D or calcium deficiency, they can
develop rickets, a softening of the bones. New studies are showing

that people of all ages need vitamin D to help them fight off
diseases by keeping their immune systems strong.

A) is found in milk
B) has been studied by scientists
C) is no secret
D) is important for good health

Answer 1

The ans is D) is important for good health
:)