What is the most densely populated city in the world?

What causes the cyclical changes in the appearance of the moon?

In which area will soil formation be greatest? a a steep slope in a warm,b wet climate a flat area in a warm,c wet climate a north-facing area on a steep slope a flat area in a cold, d wet climate description

Which of the following is not a place where hydrogen can be found on earth? a. natural gas well b. atmosphere c. water d. mine