If eras are marked by major changes in life forms, what distinguishes one period from the next

Answer;

-Periodic large-scale mass extinctions

If eras are marked by major changes in life forms, periodic large-scale mass extinctions distinguishes one period from the next.

Explanation;

The geological time scale is that the history of the planet counteracted into spans of your time marked by varied events. There are alternative markers, just like the forms of species and the way they evolved, that distinguish just one occasion from another on the geological time scale.

a researcher conducts an experiment on the secretion of a particular hormone in mice. scientists inject mice with a substance that stimulates the production of the hormone. the scientists then test the levels of hormones produced by the mice. the tool used to measure the hormones consistently detects the levels at 10 points lower than the actual hormone levels in the mice. this tool makes measurements, but the measurements aren't .

explanation:

no u