Before revision: Pressure conditions may be extremely high or low; high or low content of oxygen or carbon dioxide in the atmosphere; high levels of radiation, acidity, or alkalinity; absence of water; water containing a high concentration of salt or sugar ; the presence of sulphur, petroleum, and other toxic substances.
After revision: Pressure conditions may be extremely high or low; high or low content of oxygen or carbon dioxide in the atmosphere; high levels of radiation, acidity, or alkalinity; absence of water; water containing a high concentration of salt ; the presence of sulphur, petroleum, and other toxic substances.