How is the ammonium ion (nh4)1- and the oxalate ion (c2o4) 2- combine written in the ionic compound formed?

This large tectonic plate is bounded on three sides by whats know as the ring of fire. what is the name of this tectonic plate? a) pacific plate b) eurasian plate c) north american plate d) indo- australian plate plz it's science but there's no option for science so i picked chemistry

What’s the scientific notation for the number 6,840,000,000

The tilt of the earth's axis of rotation is responsible for the a) ocean's tides. b) size of the moon. c) brightness of stars. d) earth’s seasons.