Below is the text with the missing letters filled in and the nouns placed in the correct form:

По (Dative) лепечут осинки. На берёзке (Prepositional) светятся золотые листочки. В воздухе (Prepositional) кружится тонкая паутина. На рябине (Prepositional) висят гроздья ягод. 1. Identify noun endings

The completed exercise 229 for the 4th-grade Russian language textbook by T.G. Ramzaeva involves identifying the case of nouns and correctly spelling their endings. Completed Text for Exercise 229