Answer:
The correct answer will be option-
1. UV light strikes the skin and converts a steroid molecule into an inactive form of vitamin D.
2. Inactive vitamin D is transported to the liver where it is modified.
3. Vitamin D is activated under the influence of PTH.
4. Inactive, chemically altered vitamin D is transported to the kidneys.
Explanation:
Vitamin D is a fat-soluble metabolite which helps maintain the health of the bone by maintaining the calcium homeostasis.
The vitamin D is synthesized mainly in the liver and kidney from the biologically inactive precursor of vitamin D called ergocalciferol and Cholecalciferol.
The inactive vitamin is synthesized in the skin when the skin is exposed to UV rays. The UV rays convert the 7-dehydrocholesterol, a steroid molecule to Vitamin D3, This inactive vitamin is then transported to the liver where it is converted to 25-hydroxyvitamin D.
This vitamin D form is further metabolized in the kidney controlled and regulated by the Parathyroid glands.
The offspring of sexually reproducing organisms are all genetically unique. Because of this, sexually reproducing organisms may have more successful survival of offspring in environments that change than asexually reproducing organisms, whose offspring are all genetically identical.
1. Variable
2. Pea plants reproduce sexually.
Female and Male sex cells on pea plants (have a variety of traits) allowed Mendel to cross pollinate them.
