Look at the underlined words in the sentences from the text circle the word or phrase they refer to. Connect them with an arrow then answer the questions that follow the example sentences.
One of the biggest mysteries of science for many years has been how the dinosaurs disappeared. These amazing animals ruled earth for 160 million years. They lived everywhere.
They were the largest and most powerful animals for a large past of the history of animal life on earth. Compared with humans two hundred thousand years or so this is an amazing achievement