What is biosphere in hardwood forest

In many humans, exposing the skin to sunlight over prolonged periods of time results in the production of more pigment by the skin cells (tanning). this change in skin color provides evidence that -

The is an estimate of the fewest number of organisms a population needs to avoid extinction. this measurement will most if the number of offspring each female in the population produces increases. if the population's this measurement will most likely increase. 1 population density, minimum viable population, carrying capacity 2 decrease, be unaffected, increase 3 death rate increase, dead rate decrease

Give an example of a trait that is controlled by more than one gene.