What other weapons do sea stars have ?

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

What element has similar physical and chemical properties as boron.

How can the number of core electrons be determined from the periodic table