Is there a relationship between the amount of species lost in Earth's past 5 mass extinctions and what has occurred in the last few decades

What is a limitation of using a chemical formula, such as c6h1206, to represent a compound? the chemical formula does not show the types of elements that make up the compound. the chemical formula does not show how the atoms are connected to one another the chemical formula does not show the number of atoms of each element in a molecule. the chemical formula does not show the chemical symbols of the elements in the compound

Which kind of worm has a closed circulatory system? a planarian b fluke c pinworm d an earthworm

Explain how paleontologists use trilobite fossils as index fossils for various geologic time periods.