Which of these leads to competition between two species?
a) an overlap in the two species' niches
b) an increase in genetic diversity in one species
c) the extinction of a predator species
d) an increase in available recources
answer is a^^

primary succession occurs in essentially lifeless areas regions in which the soil is incapable of sustaining life as a result of such factors as lava flows, newly formed sand dunes, or rocks left from a retreating glacier. secondary succession occurs