Small flap of tissue that seals off the trachea.

Approximately workers each year are treated for injuries caused by lifts, jacks, or jack stands. a) 2,000 b) 5,000 c) 10,000 d) 15,000

Class iii atmospheric hazards are those involving

Earth's atmosphere is unique among the planets and is able to support life because it contains a large amount of a) oxygen b) helium c) methane d) carbon dioxide