In ecology,what is referred to as a 'niche'?

Animals living in colder regions have shorter tails and ears compared to animals living in warmer regions. This phenomenon is called:

Many tribes live in the high altitude of the Himalayas. What physiological adaptation do they exhibit?

Sal and teak are dominant in

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?

An ecological niche is defined as the: