Carbon monoxide is: only found in large cities an odorless, colorless, toxic gas healthy to breath in a danger when driving on the open highway

Carbon monoxide is an odorless, colorless, toxic gas

Explanation:

Carbon monoxide is gas made up one carbon and one oxygen atom. The chemical formula of the gas is CO.

It is a colorless and an odorless gasObtained from incomplete combustion of carbon containing compoundsHigh concentration of this gas in human body can lead to death. Hence,toxic gas.

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .