Why mammals of the colder region generally have shorter ears and limbs?
$I.$ To minimize their surface volume ratio
$II.$ To minimize heat loss
$III.$ To maximize their surface volume ratio
$IV.$ To maximize heat loss
Choose the correct combination from the given option
Regulators are also called
Consider the following four statements $(1-4)$ about certain desert animals such as kangaroo rat.
$(1)$ They have dark colour and high rate of reproduction and excrete solid urine.
$(2)$ They do not drink water, breathe at a slow rate to conserve water and have their body covered with thick hairs.
$(3)$ They feed on dry seeds and do not require drinking water.
$(4)$ They excrete very concentrated urine and do not use water to regulate body temperature.
Which two of the above statements for such animals are true ?
Many fishes of freshwater can't live in sea water and vice -versa because of