The word survivors is a plural, common noun which is the direct object of the sentence. The direct object in this sentence is a subject complement, the object of a linking verb that renames the subject.
The answer is birds. Naming parts are called nouns.
Yup. All the birds you see today are dinosaurs, therapods.
Archeoptyrix, Crocodiles and crocodile like creatures... Small mammals (which we evolved from), well... thats almost all known so far... although Archeoptyrix evolved into the modern birds, its still a survivor!
The birds are singing again!
It will almost always be an adverb phrase, followed by a comma. e.g. "In the spring, birds fly south." It can, rarely, be an adjective. e.g. Of (among) the survivors, most were badly injured.
not worth consideration; unimportant:
The subject is "birds".
what are the abstract nouns in this sentence the birds live in their habitat with no fear
Birds migrate to the South for the winter time.
not worth consideration; unimportant:
No chance. The dinosaurs died out hundreds of millions of years ago. Birds are descended from the survivors.
birds - simple subject masses of birds - complete subject