Explanation:
Radioactive dating works on the principle that a radioactive isotope can decay into the stable daughter nuclei at a constant rate. Geologist generally use the principle for half life. Half life is the time required for half of the radioactive substance to decay. This is constant for a particular element.
The lowermost level of the epidermis is known as stratum germinativum. It is the bottom of the epidermis and cells divide constantly and push older cells upward. It is mainly complete up of basal keratinocyte stem cells which can be well thought-out the stem cells of the epidermis. They distribute to practice the keratinocytes of the stratum spinosum which transfer rapidly. Other types of cells originate within the stratum basale are melanocytes which is pigment making cells, langerhans cell which is immune cells and merkel cells such as touch receptors.
The correct answer is the last one: Decreased variation in tail feather color because the only reason for variation was selection pressure.
If the female peacock were to base her selection criteria on something other than the colors of the male's tail feathers, the latter would not play such an important role anymore and therefore there would no longer be the pressure of needing to have the brightest, most variant and vibrant colors.
