When does incomplete combustion occur?

Select all of the methods through which a drug can enter your body. injection swallowing inhalation absorption

As air becomes more dense, (select all that apply) o. air weighs less o. gas molecules are closer together o. air is colder o. air weighs more o. gas molecules are further apart o. air is hotter

As changes in energy levels of electrons increase, the frequencies of atomic line spectra they emit