Read the passage carefully and answer the questions that follow:

 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 reading words. Could any of these mammals be more intelligent than man? Certainly the most common argument in favour of man's superiority over them is that we can kill them more easily than they can kill us. On the contrary, the more we discover about these remarkable creatures, the less we appear superior when we destroy them.

Questions: 

(a) What are mammals? 

(b) Comment on the nature of dolphins. 

(c) How do dolphins behave in their community? 

(d) How do dolphins communicate? 

(e) How do men substantiate their superiority over dolphins?