Respuesta :
Trilobites were exclusively marine animals. They were first appeared at the beginning of the Cambrian Period. In the context Jellyfish existed before trilobites and ammonites.
What is method to determine fossil age?
To find the age of fossil, scientists use some type of clock to determine the date it was formed.
Geologists usually use radiometric dating procedures which is based on the natural radioactive decay of some elements such as potassium and carbon, as reliable clocks to date ancient events.
In the given context, jellyfish fossils are found lower than trilobite fossils, and trilobite fossils are found lower than ammonite fossils. Which determines that jellyfish existed before trilobites and ammonites.
Thus, the correct option is B.
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