The indigenous groups of individuals in distinct parts of the world possess different skin colors from other groups of individuals. Following are the different kinds of evidence, which supports the idea:
1. The individuals would have moved around the globe, however, they would have still kept their skin color DNA.
2. There also would have been more individuals living all over the globe and the skin color of the individuals would have changed gradually with time.
3. Living at higher altitudes would have resulted in more variation as the amount of exposure would have been different from the individuals moving around the world.
The environment plays an important role in the determination of the phenotype of the organisms. Some traits are controlled by the environmental as well as by the genetic factors.
The skin color is an example of polygenic trait in which more than two genes are involved for the phenotype of an individual. The individual have their fixed DNA for the skin color. The individual's DNA responsible for the skin color gets change over time due to the evolution and according to the environmental factors as well. The uneven geographical distribution and temperature influence has caused more variation in the skin color.
There are four main stages in the water cycle. They are evaporation, condensation, precipitation and collection. Let's look at each of these stages. Evaporation: This is when warmth from the sun causes water from oceans, lakes, streams, ice and soils to rise into the air and turn into water vapour (gas).
HIV in fact kills the immune system cells causing our body cannot fight off infections and diseases from entering our body. this creates our immune system to become weaken.
The precise definition of pH is "the negative common logarithm of the activity of hydrogen ion in solution". For practical purposes, the activity is approximated as concentration in moles/L: pH = - log 10 ([H+]) .
