Answer: The causes of extinction of the dinosaurs were- A huge meteorite of diameter 10-15 km, hit the earth about 65 millionyears back and caused the global extinction of plant and animal species upto 75-80%. B Volcanic eruptions such as Deccan traps are also an evidence of the dinosaur's extinction. C The Cretaceous-Tertiary (K-T) boundary also supports the evidence of that global mass extinction, as Iridium (an element) is present that suggests a mass extinction event.