In the following passage some words have been deleted. Fill in the blanks with the help of the alternatives given. Select the most appropriate option for each blank.
Comprehension:

Throughout the ages, birds have been a source of wonder to all who have (1)______ their soaring flight or listened to (2)______ sweet songs. As a group, birds are (3)______. They are the only creatures covered (4)______ feathers. This evolutionary development (5)______ birds from all other animals.