Which of the following words in the passage aptly mean, “No longer in existence”?

Read the passage and answer the question that follows.

DINOSAURS

The word “dinosaur”, coined by Sir Richard Owen in the year 1842, literally means “terrifying lizard.” Long, long before humans had been on the earth, the world was ruled by dinosaurs. They were gigantic, land dwelling reptiles that lived in the Mesozoic Era or the “Age of Reptiles” around 245 million years ago. For around 165 million years, dinosaurs walked on the earth. Then, around 65 million years ago, the dinosaurs and most of the animals of the era, except some ancestral birds and some fish, died out and became extinct for unknown reasons. What we know of the dinosaurs is only from studying their fossils. The proof of dinosaurs makes us think of a world that was very different from what we see today.