pH of about 7, except for in stomachs and digestive tracts
7
Carbon doesn't get into living things. All living things are constituted of carbon. This is why we have carbon inside us.
Bases can affect living things by altering the pH of their internal environment. Changes in pH can disrupt biological processes and lead to cellular damage or dysfunction. Additionally, direct contact with strong bases can cause irritation or burns on living tissue.
Biologist
Neon is chemically inert. It doesnt react with any other element and (to the best of my knowledge) has no role in living things. So I would comment that the element neon is not found inside living things.
Plants.
organelles
Viruses depend on living cells because they reproduce inside of them.
Absorption of carbon dioxide from the atmosphere modify the pH of waters; also the pollution from human activities.
Living things keep the proper condition inside in a number of ways. Organisms use osmosis to control molecule intake, and temperature controlling mechanisms.
Sodium is found in table salt, battries and streetlights. Although these are not living things, i dont think sodium is found in living things. Although it may be in plants!
Rainwater with a pH below 5.6 is called acid rain, which is very harmful to the enviroment. It can cause buildings, statues and all other non-living things to decay over a period of time, and is extremely harmful or deadly to living things.