Final answer:
Sickling of red blood cells in sickle-cell anemia can be triggered by travel at high altitude and vigorous exercise due to decreased oxygen availability or increased oxygen demand, respectively.
Step-by-step explanation:
Sickling of red blood cells can be produced in those with sickle-cell anemia by travel at high altitude and vigorous exercise.
Sickle-cell anemia is a genetic disorder where the production of an abnormal type of hemoglobin, known as hemoglobin S, leads to the characteristic sickle or crescent shape of erythrocytes (red blood cells), particularly under low oxygen conditions.
This shape change makes the cells rigid and prone to getting stuck in capillaries, impairing blood flow and oxygen delivery, and leading to various health complications.
Conditions that decrease oxygen in the blood, such as travel at high altitude where oxygen levels are lower, or vigorous exercise which increases oxygen demand, can induce sickling of the red blood cells in affected individuals.