Complete the sentences with one of the following wordes: endangered,exting,rare. 1 a species is a group of animals or plants with a small number of organisms worldwide,usually fewer than 10,000. 2 an animal is when there are not many of its kind alive and it could soon become 3 there are many species that could soon become 4 dinosaurs lived on our planet a long time before they became 65 million years ago.