An epoch is longer than an era.
Answer:
to break down food into nutrients
A paleontologist can use radiometric dating (also known as carbon dating), to determine the age of a fossil. They do this by measuring the decay of isotopes in either the fossil itself or the rocks associated with it. A carbon-14 isotope takes about<span> 5,730 years to halfway decay, knowing this information paleontologists can date a fossil by how long the fossil has been decaying with the use of special tools.
http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/cardat.html
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<span> the answer is commensalism</span>