1.   As a warning, Gore waved in front of him a rubbery replica of a human lung turned black from cigarettes.

2.   Asbestos is carefully monitored because its fibers, once embedded in human lungs, can cause respiratory problems, including lung cancer.

3.   A pair of human lungs has a total of five lobes.

4.   Different countries that made anthrax weapons had different techniques for achieving the small size needed to penetrate deeply into human lungs.

5.   Doctors say the sulfur attaches to tiny soot particles that penetrate human lungs where it mixes with water to form a potent acid, damaging the tissues.

6.   For instance, commercial crop-dusters usually dispense liquids, and their nozzles produce droplets far too large for sailing deep into human lungs.

7.   For instance, commercial crop-dusters usually dispense liquids, and their nozzles produce droplets far too large to get deep into human lungs.

8.   For instance, he said, the microscopic particles of an infective mist had to be just the right size to penetrate deep into human lungs and start infections.

9.   For instance, while asbestos fibers wreak havoc in human lungs, they barely affect lung tissue in mice.

10.   Particles must be small in size to penetrate deep into human lungs, where they can start a lethal infection.