Weather reporters have to give out a lot of information. That's why they use pictures. The pictures help them tell us about the weather without using so many words. Weather reporters need to know where the cold air is. They need to know where the warm air is. They have to know where it is raining and what types of clouds are in the area. Their reports need to be correct, but they also need to be short. The pictures help weather reporters get the information out in a fast way.

Which sentence best describes the main idea of the paragraph?

Dolphins are regarded as the friendliest creatures in the sea and stories of them helping drowning sailors have been common since Roman times. The more we learn about dolphins, the more we realize that their society is more complex than people previously imagined. They look after other dolphins when they are ill, care for pregnant mothers and protect the weakest in the community, as we do. Some scientists have suggested that dolphins have a language but it is much more probable that they communicate with each other without needing words. Could any of these mammals be more intelligent than man? Certainly the most common argument in favor of man's superiority over them that we can kill them more easily than they can kill us is the least satisfactory. On the contrary, the more we discover about these remarkable creatures, the less we appear superior when we destroy them.

It is clear from the passage that dolphins ----.

Referring to words of a previous speaker.