Answer:
Index
Explanation:
An index fossil can be used to identify a specific period of time. Organisms that make good index fossils are distinctive, widespread, and lived briefly. Their presence in a rock layer can be used to identify that period of time over a large area.
Answer:
La función básica del aparato respiratorio es la respiración. Consiste en llevar el oxígeno del aire a la sangre y eliminar el anhídrido carbónico (CO2) al aire. Este intercambio de gases se produce en el interior de los pulmones.
Explanation:
To prevent blood flowing back after each heartbeat. They ensure that the blood flows only in one direction (back to the heart).
Because with that the mitochondria will make ATP (energy) for the cell and your body
I just learned that today XD
