During early ages, the alkaline hot liquids from the vent met the acidic cold ocean water. The acidic ocean water produced a nat
ural gradient across mineral wall in rocks that are rich in catalytic minerals. This difference in conditions converted and hydrogen into organic carbon-containing molecules. These can react with each other to form organic molecules, such as nucleotides and amino acids.
The alkaline hot liquids reacts with the acidic cold ocean water to form minerals which are in the form of salts. When the negative ion of a base react with the positive ions of an acid, salts are produced.
the first answer as blood needs to be oxygenated to be passes round the body then when its deoxgenated it will return to the heart to be pumped around the body again