IMAT 2021 Q29 Biology

Hi, I know that 2 and 3 are correct but I can’t figure out why 1 is correct, does anyone have an idea?

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At lower partial pressures (concentrations) of oxygen, our body must still fulfill the needs of our organism, so more RBCs differentiate from the stem cells in our bone marrow in order to saturate as much as physically possible to deliver enough oxygen to our cells.


Oh okay that makes sense thanks!


I got it . This mean like forming any blood cells … rbc or wbc when needed by body ?

@MacaROHN can u please explain 3rd option?

Of course! Increased differentiation of bone marrow stem cells basically means the bone marrow producing more blood cells (thus an increase in number of blood cells in the blood), red blood cells are produced in the bone marrow when the bone marrow stem cells differentiate into red blood cells.
Hope this was clear


Yeah thank you so much!

can u please explain 2

Bacterial infection causes red blood cells to explode, then haemoglobin is released.

hey, i see what your reasoning was for this, however if the infection causes the cells to burst then the blood cell count would decrease so this can’t be the cause.

The reason why blood cell count increases in response to a bacterial infection is white blood cells (monocytes, lymphocytes, granulocytes) are recruited and proliferate in the blood to fight it off