Several billion years ago, which gas was the least prevalent in the atmosphere? a: nitrogenb: oxygenc: carbon dioxided: water vaporneed !

Which of the following is not a difference between a compound and a mixture? 1 some mixtures are homogenous, while others are heterogeneous. all compounds are homogeneous. 2 mixtures are homogeneous while compounds are heterogeneous. 3 no chemical bonding occurs between the components of a mixture. the properties of atoms and molecules are not changed when they become part of a mixture. 3 mixtures can be separated by physical means, for example, straining, filtering, or evaporation. 4compounds can only be separated into their constituent atoms by chemically breaking bonds.