If resources get low, the population's numbers can decrease.
Relative dating<span> is the science of determining the</span>relative<span> order of past events (i.e., the age of an object in comparison to another), without necessarily determining their absolute age, (i.e. estimated age).</span>
People migrate to the new lands, populate, build cities, created businesses, trade, settle.
Volcanic eruptions can destroy building that store resources, burn trees, kill animals and make land not suitable for farming etc
