Squid blood Haemoglobin uses Copper to bind Oxygen, while most animals use Iron. Chlorophyll is very similar to Haemoglobin, but uses Magnesium instead of Iron.

Squid blood Haemoglobin uses Copper to bind Oxygen, while most animals use Iron. Chlorophyll is very similar to Haemoglobin, but uses Magnesium instead of Iron. All life on Earth needs Phosphorus to form DNA.