'People who live at high altitudes often have thicker blood, to deliver more of this gas to body cells'
oxygen
BLOOD TEST: People who live at high altitudes often have thicker blood, to deliver more of this gas to body cells
People who live at high altitudes often have thicker blood, to deliver more of this gas to body cells
People who live at high altitudes often have thicker blood, to deliver more of this gas to body cells
BLOOD TEST
oxygen
BLOOD TEST