James Watson and Francis Crick discovered the double helix shape of DNA. They based their work on that of Rosalind Franklin who also saw a helix shape when he took images of different DNA proteins.
Some examples of homeostasis include:
- Blood glucose concentration regulation
- Blood water potential
- Temperature regulation
I don't know the answer options, but it would probably either be phase of matter or physical change.
The answer is C) Increase her daily vitamin D intake