Of the following statements there are two statements both of which cannot be true. Which are these two statements? (i) Dinosaurs became extinct in the Cretaceous-Paleolithic era (ii) Dinosaurs were destroyed after the invention of gunpowder (iii) Dinosaurs failed to adapt to environmental changes (iv) Dinosaurs might have been saved if they had been protected in zoos

Statement (ii) which says "Dinosaurs were destroyed after the invention of gunpowder" is incorrect. The reasons are:-

• Dinosaurs went extinct about 65 million years ago (at the end of the Cretaceous Period), after living on Earth for about 165 million years. 
• Gun powder is thought to have originated in China, where it was being used in fireworks and signals by the 10th century (around 1100 years ago)

Statement (iv) which says "Dinosaurs might have been saved if they had been protected in zoos" is an illogical statements because :-

• Geological evidence indicates that dinosaurs became extinct about 66 million years ago, at a time when there was worldwide environmental change resulting from the impact of a large celestial object with the Earth and/or from vast volcanic eruptions.
• This was many millions of years before the first modern humans, Homo sapiens, appeared.

Hence statement (ii) and (iv) are not true.