1. which of the following elements is NOT multivalent? A. Be

B. Cu

C. Pb

D. Fe

This active feature of earth's crust in building mountain ranges as well as islands. this feature is a a) cavern. b) earthquake. c) mountain. d) volcano.

Provide a stepwise curved arrow mechanism that fully explains the outcome of the reaction shown below. oh нао* heat он

Match the mixture with the substance// i really need on this guys (it’s a pic btw)