A chemical substance is a material with a specific chemical composition. A common example of a chemical substance is pure water; it has the same properties and the same ratio of hydrogen to oxygen whether it is isolated from a river or made in a laboratory.
A common unintentional overdose in young children involves multi-vitamins containing iron. Iron is a component of the hemoglobin molecule in blood, used to transport oxygen to living cells.
Activating oxygen can produce compounds called radicals that put oxidative stress on cells. Such stress could ultimately lead to cancer and other diseases. John Simon
Among the notable things about fire is that it also requires oxygen to burn - exactly like its enemy, life. Thereby are life and flames so often compared. Otto Weininger
An oxygen tent consists in a canopy placed over the head and shoulders or over the entire body of a patient to provide oxygen at a higher level than normal.
Basic human contact - the meeting of eyes, the exchanging of words - is to the psyche what oxygen is to the brain. If you're feeling abandoned by the world, interact with anyone you can.
Martha Beck
Basic human contact - the meeting of eyes, the exchanging of words - is to the psyche what oxygen is to the brain. If you're feeling abandoned by the world, interact with anyone you can. Martha Beck
