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
The action or fact of forming a united state that seems as the best answer
Population refers to an array of organisms of the similar species, which thrives in a particular geographical region and interbreed. The three main characteristics of a population are density, size, and dispersion.
The density signifies towards how many organisms are thriving in a specific region. The size refers to how big a population is, and dispersion signifies towards the degree of spreading of the particular population.