True breeding is when nature had to do with the breeding and Mendel didn't interfere with the breeding of the plants to get a certain offspring
100% of the offspring would have the genotype Bb, and the phenotype of the blue color.
Answer:
Make sure everyone meets criteria.
Not taking supplements( As some may contain Vit D)
No tanning beds
make sure no one has a hypoactive response to vitamin d through whatever way. Injection, capsule, spray.
Check for genetic conditions or cancers like melanoma which indirectly affect vitamin d levels
Explanation:
These are some of the main things to look out for
