Which two conditions must exist in a popularion for natural selection to take place?
a)most of its members must look like the same type of organism
b) the group must consist of I individuals that arw genetically identical
c) there must be a genetic variation among the individuals in the population
d) some of its members must be better suited to the environment than others

needed for natural selection to occur: reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population. If they are met, natural selection automatically results.

volcanoes (an event in the geosphere) release a large amount of particulate matter into the atmosphere. these particles serve as nuclei for the formation of water droplets (hydrosphere). rainfall (hydrosphere) often increases following an eruption, stimulating plant growth (biosphere).