Natural selection. darwin hypothesized that there requisites for natural selection to occur and that there are definite steps to natural selection. note the two models seen here. both of the models illustrate an important requisite for natural selection. that is:

What is true about all plutons? they form below earth’s surface. they form near earth’s surface. they form above earth’s surface. they cut across other rock layers.

When wind creates a sand dune, the sheltered side of the dune is less steeply sloped than the windward side has the same incline as the windward side is more steeply sloped than the windward side

Apopulation of bears has genetic diversity. some of the bears have an allele that gives them thicker fur. due to climate change, the winters have gotten colder in their habitat. now the bears with thicker fur are becoming more common in the population. a.) which type of bear is selected for in the coldest ecosystem? b.) what must be the other allele for the type of fur, and what term would you use to describe the fact that the allele is becoming less common in the colder climate? c.) describe the change in the bear population in terms of changing allele frequencies and phenotypes d.) is this an example of natural selection