A zircon in a lava flow is going through radioactive decay. By the time a sample is collected by a geologist, only six percent of its original parent material still remains. How many half-lives has the zircon experienced?

Awatershed is a piece of land that drains water into a particular stream, lake, or river. which of the following factors often negatively impacts the water quality in a watershed? a.) wetlands b.) pollution c.) irrigation d.)rainfall

Eastern europe’s population growth can be attributed to these factors. select all that apply migration

Unlike other andean nations, chile has a relatively small population of mestizos people of european descent indians people of asian descent