Is piedras a stem changing verb?

Me i need on math i’m super confused on my homework

  frgbvrewgafvra vfsaf vr f farew f

Is the common name of the main square in central mexico city. prior to the colonial period, it was the main ceremonial center in the aztec city of tenochtitlan. however, it is almost always called the zócalo today.

  mercadillo is a  market, or  marketplace, is a location where people regularly gather for the purchase and sale of provisions, livestock, and other goods.