Which element below is least reactive

Which best describes why nh4+ can form an ionic bond with cl-?

Which of the following true? a_volcanoes and earthquakes often near the plate boundaries. b_volcanoes occur whereve there are tall mountains. c_earthquakes cause volcanoes in the same location to erupt violently d_volcanoes and earthquakes occur only where plates are colliding with each other

All of the following are part of the biosphere except