How can fossils be useful to geologist? Give one example in your explanation

Fossils can show geologists what type of animals/ plants lived in a given area and how long ago

Fossils are useful in geography because with fossils they figure out how animals life be like and how early humans lived like.

So  if  the sum of the enthalpies of the reactants is greater than the products, the  reaction  will be  exothermic.  if  the products side has a larger enthalpy, the  reaction  is  endothermic. you may wonder why  endothermic reactions, which soak up energy or enthalpy from the environment, even happen

Do you have a picture for this problem?