The answer is polygenic inheritance.
Many physical characters (traits) depend on many different factors, each of which is determined by different genes. This is called polygenic inheritance.
For example, the color of the skin in humans. The color of the skin results from the interactions of several factors determined by different pairs of genes:-Certain genes could affect the metabolism of skin melanocytes.-Other genes can determine the distribution of melanin in the thickness of the skin.-Some genes could determine the relative amounts of each of the two possible types of melanin.-Others may affect the production of certain hormones involved in the activity of melanocytes.
Answer:
Index fossils
Explanation:
The index fossils are the fossils that come in very handy for the geologists when it comes to identifying or dating rock samples or other fossils. The reason for this is that the index fossils have already been dated. They are fossils that are very commonly found, wide dispersed, are easy to be identified, and are limited to only a certain geological period. These characteristics make them an excellent indicator for the dating of the rock layers in which they are found, or the fossils found in the same layers with them, without conducting further examinations.
C Improper signaling by the right-left axis during development
