The word structure comes from the Latin sternere, which means "to stretch, extend." Which vocabulary word has the same root?

stratum

seized

waft

ventilator

A. Stratum

One of the definitions of stratum (root word sternerne) means " one of a series of layers, levels, or gradations in an ordered system". This ties into the definition of the root word (to stretch, extend), because the layers keep adding, stretching, extending in order to create the stratum.