Impact of over population and under population?

One disadvantage that darwin faces today is w. enemy attacks x. natural disasters y. lack of land bridge z. high population density

Which of the following describes the relationship between elements of an ecosystem

Which statement is an accurate description of life in mongolia in recent years? the majority of the population now lives in cities. after a brief period of democracy, communists regained control of the government. subsistence farming remains the primary economic activity in the country. relations between mongolia and china are now tense. -gradpoint