DIRECTION: Read the given passage carefully and answer the questions 14 and 15. Every year, different birds fly over long distances to find the best ecological conditions for feeding, breeding and raising their young ones. This is known as migration. The migratory birds undergo some changes before setting off on a journey. Not all birds migrate. Some changes are seen in bird's body before it migrates. Which of the following is correct regarding this?

• A.  The feathers grow thicker.
• B.  The muscles get more dense.
• C.  The fat gets collected under the skin.
• D.  Eyes become keener.