The mineralized remains of organisms and the rock layers in which they are found * Sedimentary Layers
O Fossils
O Diversity
Extinction
Fossil Record

hi~~

i would say that hybridization occurs frequently in nature, because there are many types of hybrids that have occurred naturally, such as the mule (male donkey + female horse)

b. read the phase at the intersection of any given temperature and pressure.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".