Is the Vitamin D that our skin makes when exposed
to the sun's rays natural or synthetic?

The Vitamin D that is made when exposed to sun rays are natural. Your skin naturally intakes the sunlight as Vitamin D.

Explanation:

This happens naturally for everyone, although some people are able to make less Vitamin D than others.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

i would say b

explanation:

but i think i would need more information than that