Choose correct pair :

$(1)$ Salt concentration in inland water – $30-35\%$

$(2)$ Salt concentration in the sea – $5\%$

$(3)$ Salt concentration in hypersalinelagoon – $>100\%$

Body compensates low oxygen availability at high altitudes by

$I.$ increasing $RBC$

$II.$ decreasing binding affinity of haemoglobin

$III.$ increasing binding affinity of haemoglobin

$IV.$ increasing breathing rate

$V.$ decreasing breathing rate

Choose the correct option for given statement

Give differences : Ectotherms and Endotherms

A characteristic which enables an organism to live in an environment is called

Ravi, who lived at sea level, had around $5$ million $RBC$ per cubic millimeter of his blood. Later when he lived at an altitude of $18,000 ft$, showed around $8$ million $RBC$  per cubic millimeter of blood. This is an adaptation because