There have been at least five mass extinction events on earth. true or false?

The answer is True..

True

Explanation: There have been five major mass extinction that took place in the history which led to the extinction of many different kinds of species that were once present on earth.

The major five extinctions were named as follows:

First mass extinction took place during the End Ordovician, where 86% of species were lost that took over 444 million years ago,

— Graptolite 2-3 cm length

Second mass extinction took place during the Late Devonian, where 75% of species were lost which took place over 375 million years ago.

— Trilobite, 5 cm length

Third mass extinction took place during the End Permian, where 96% of species lost took place over 251 million years ago.

— Tabulate coral, 5 CM

Fourth mass extinction occurred during End Triassic,where 80% species lost took place that took place 200 million years ago,

— Conodont teeth 1 mm

Fifth occurred during  End Cretaceous, where 76% of species lost took place that occurred over 66 million years ago,

— Ammonite 15 cm length

Only one reactant yields 2 or more products. meaning you will only have 1 product and it will break down into 2 or more products. eg. h2o -> h2 + o2