What special feature allows birds to fly?

Instead of heavy jaws and teeth, they have lightweight beaks. And instead of fur, they have feathers. These are light, streamlined and cleverly adjustable for flight control. Their bones are also hollow (pneumatised) making them lighter for flight.

Explanation:

lol its to easy and almost common sense

ysosomes are membrane-bound vesicles that contain digestive enzymes, such as glycosidases, proteases and sulfatases. lysosomal enzymes are synthesized in the endoplasmic reticulum (er), are transported to the golgi apparatus, and are tagged for lysosomes by the addition of mannose-6-phosphate label.

explanation:

the answer to your question is b