A substance found in the blood that acts as a precursor in the biosynthesis of ABO blood group antigens.

Abbreviation for haemoglobin, a protein in red blood cells that carries oxygen from the lungs to the tissues.

The natural environment in which an organism lives, including both biotic and abiotic factors.

The tendency of a species to select a particular type of habitat over others due to factors such as food availability, climate, and shelter.

A functional definition of habitat based on the specific needs of an organism, such as food, nesting sites, and climate.

The process by which an organism becomes less responsive to repeated stimuli that are not harmful or rewarding.

The iron-containing molecule that binds oxygen in haemoglobin, essential for the transport of oxygen in the blood.

The accumulation of menstrual blood in the vagina, typically due to an obstruction in the vaginal opening.

The process of blood cell formation, including the production of red blood cells, white blood cells, and platelets.

A copper-based molecule that functions as an oxygen carrier in the blood of some arthropods and mollusks, analogous to hemoglobin in vertebrates.