$A$ decrease in the $pH$ of blood leads to:

Define oxygen dissociation curve. Can you suggest any reason for its sigmoidal pattern?

The Haldane effect is caused by which of the following?

People living at sea level have around $5 \; million$ $RBCs$ per cubic millimetre of their blood,whereas those living at an altitude of $5400 \; m$ have around $8 \; million$. This is because at high altitude:

Haemoglobin is a red-colored,iron-containing pigment present in $RBCs$. $O_2$ binds with it in a reversible manner to form..........

Given below are two statements.
Statement $I$: Carbonic anhydrase enzyme is found in $RBCs$ and is absent in plasma.
Statement $II$: The rate of formation of carbonic acid is very high inside $RBCs$ than in plasma.
In light of the above statements, select the correct answer from the options given below.