Give four nutrients that are sensitive to light and four sensitive to heat

Actually, most vitamins are sensitive to heat, that's why over cooking your vegetable will decrease it's nutrients

Nutrients that are Sensitive to Heat :
- Vitamin C
- Vitamin B1
- Viatmin B5
- Vitamin B9
 
But some of them also react to light ( our body increase the production of some of this nutrients if exposed to light)

- Vitamin A
- Vitamin D
- Vitamin E
- Vitamin B-Complex

What happens to the influenza virus every 20-40 years and why?