Which of these structures contribute to the ability of birds to fly? Check all that apply. wings
light, nearly hollow bones
solid, heavy bones
contour feathers
air sacs connected to lungs
three-chambered heart
large chest muscles

A, B, D, E, G

Explanation:

found out the hard way,  edge. 2021

worldwide, 780 million people do not have access to an improved water source. an estimated 2.5 billion people lack access to improved sanitation (more than 35% of the world's population)