Ques: Q: Birds have light-weight bones that are filled with what? Choices: - water - proteins - blood - air A:
Ans: air

Ques: Q: Which gas moves from the blood in the capillaries into the air? Choices: - nitrogen - carbon monoxide - oxygen - carbon dioxide A:
Ans: carbon dioxide

Ques: Q: What is the term for chordates with a vertebral column and endoskeleton of cartilage and bone? Choices: - am - insect - mammel - vertebrate A:
Ans: vertebrate

Ques: Q: Secondary pollutants form from chemical reactions that occur when pollution is exposed to what? Choices: - humans - water - air - sunlight A:
Ans:
sunlight