Question

The rare earth elements include

Answer 1

I tried the lanthanide series and the alkali metals and it was wrong, I think the only other option would be the lanthanide series and the actinide series.

Sorry!!!

Answer 2

The rare earth elements include the lanthanide series, scandium and yttrium. They are a set of seventeen chemical elements in the periodic table. They really are not that rare but they occur together in nature and are hard to separate from one another.