What is formed by the populations of different species living together in a common habitat?

Penguins are found in .............. .

The part of the earth where life exists is made up of:

Which of these is/are considered the major biomes of the world?

The vast majority of animals and nearly all plants cannot maintain a constant internal environment. What is this called?

Just as a person moves from Delhi to Shimla to escape the summer heat,where do thousands of migratory birds migrate from the extremely cold regions of Siberia and the North Pole?