4. DNA sequence comparison
5. Random mutations
reproductive cells like eggs and sperm
More than 90% on the crust is composed of silicate minerals. Most abundant silicates are feldspars<span> (</span>plagioclase<span> (39%) and alkali feldspar (12%)). Other common silicate minerals are </span>quartz<span> (12%) </span>pyroxenes<span> (11%), </span>amphiboles<span> (5%), micas (5%), and clay minerals (5%).</span>
So they can say the number quicker.
