An athlete's red blood cell (RBC) count and haemoglobin levels can change as their body adapts to different environments. The table below shows the mean RBC count and mean haemoglobin concentration of an endurance runner before and after a 6-week acclimation period at a high-altitude training camp.

Measurement Phase	Mean RBC Count ( $cells/dm3\times 10^{12} \text{ cells/dm}^3$ )	Mean Haemoglobin Concentration ( $g/dm3\text{g/dm}^3$ )
Sea Level (Pre-training)	$4.4$	$140$
High Altitude (Post-training)	$5.1$	$161$

Calculate the percentage increase in the mean haemoglobin concentration of the athlete after high-altitude training compared to sea level.

Explain how an increase in haemoglobin concentration helps to improve an athlete's endurance performance.

Measurement Phase	Mean RBC Count ( $cells/dm3\times 10^{12} \text{ cells/dm}^3$ )	Mean Haemoglobin Concentration ( $g/dm3\text{g/dm}^3$ )
Sea Level (Pre-training)	$4.4$	$140$
High Altitude (Post-training)	$5.1$	$161$

Calculate the percentage increase in the mean haemoglobin concentration of the athlete after high-altitude training compared to sea level.

Explain how an increase in haemoglobin concentration helps to improve an athlete's endurance performance.

2.2 Animal tissues, organs and organ systems

Question 23

Markscheme

2.2 Animal tissues, organs and organ systems

Question 23

Markscheme

2.2 Animal tissues, organs and organ systems

Question 23

2.2 Animal tissues, organs and organ systems Questions

2.2 Animal tissues, organs and organ systems

Question 23

2.2 Animal tissues, organs and organ systems Questions