1. River-valley civilizations developed in Sumer, Egypt, China, and the Indus River Valley. After following the procedures in the Planning a Compare and Contrast Essay worksheet, write an essay comparing and contrasting these civilizations .PL HELP

Which statement correctly describes metallic bonds? a. they form when certain atoms lose electrons and other atoms gain electrons. b. they involve an attraction between anions and cations. they always involvpoth a metal and a nonmetal. d. they can only form between atoms of the same element. e. they form because electrons can move freely between atoms.

Analyze how limestone is weathered and identify the features that are formed as a result of this dissolution

Acompound has a molecular weight of 12.124 atomic mass units and the empirical formula c3h40. what is the molecular formula of the compound?