Question

lesson: secondhand smoke
secondhand smoke contains more than
chemicals, including carbon monoxide, nicotine, and
formaldehyde. these chemicals are released into the
air as a complex mixture of gases and particles, which
can linger long after smoking has ceased.
about
of the chemicals found in
secondhand smoke are known to cause cancer. these
include benzene, vinyl chloride, and polonium - 210.
exposure to these carcinogens can increase the risk of
lung cancer, as well as cancers of the throat, mouth,
and other organs.
of the chemicals in secondhand
smoke are classified as toxic substances. examples
include hydrogen cyanide, ammonia, and toluene.
these toxins can cause immediate and long - term
health problems, such as respiratory irritation,
cardiovascular damage, and neurological issues.
7,000
70
hundreds

Explanation:

Second - hand smoke contains over 7,000 chemicals. Around 70 of them are known carcinogens and hundreds are toxic substances.

Answer:

First blank: 7,000
Second blank: 70
Third blank: Hundreds