Please help me due today

A. describe the model of urban structure most often observed in mega-cities in developing countries. explain how this model differs from common urban structures in north america. b. describe at least two factors leading to the growth of mega-cities in developing or least-developed countries. c. identify and explain two factors that led to the formation of squatter settlements in mega-cities in developing countries.

This is science by the way which of the following is an example of an environmental pressure a. the air pressure in the atmosphere b. a lake that is gradually running out of water c. a fight between two members of the same species d. breeding between two members of the same species

Why does the blending of many different diciplines present both challenges and opportunities to enviromental scientist?