Cells

Haemoglobin - combine with oxygen

Biconcave shape - large surface area to volume ratio, promote efficient absorption and release of oxgyen

Absence of nucleus - more space to carry oxygen in cytoplasm

Flagellum - to propel the cell to meet the ovum for fertilization

Acrosome - to release enzymes that digest the wall of the ovum

Many mitochondria in cell - to provide energy to cell to propel to the ovum for fertilization