Which is part of the convection cycle in earths atmosphere? a. hot, denser air rises
b. cold, denser air rises
c. hot, less-dense air rises
d. cold, less-dense air falls

Which is special about a dc circuit ? a. it has both series and parallel components b. it has only series or only parallel components c. charge moves in a single direction d. charge moves back and forth quickly

Which magnetic property best describes a magnet’s ability to act at a distance? magnets are dipolar. magnets attract only certain objects. magnets have magnetic fields. magnets can transfer their properties to certain materials.

Iron is a transition metal with multiple oxidation numbers. (answer the following) a. what is the iron (ii) ion? how does it differ from the iron (iii) ion? b. if iron were to bond with oxygen, predict the formula for each oxidation number of iron. c. how would each formula be named?