Ex. 10. Fill in the missing words in the sentences below. Choose from the following ones given in the box. emerge, the solar system, ape-like-men, arrived, species, invented, concept, has been around, exists, permanent settlements, develop, alter Planet Earth is 4,600 million years old If we condense this inconceivable time-span into an understandable ...(1) we can liken Earth to a person of 46 years of age. Nothing is known about the first 7 years of this person's life, and whilst only scattered information ... (2) about the middle span, we know that only at the age of 42 did the Earth begin to ...(3). Dinosaurs and the great reptiles did not ...(4) until one year ago, when the planet was 45. Mammals ...(5) only 8 months ago; in the middle of last week manlike apes evolved into ...(6), and at the weekend the last ice age enveloped the Earth.