The purpose is to show North,South, East, and West. Sometimes it shows northwest,northeast,southwest, and southeast as well.
<span>There are lots of countries that do not have volcanoes, some of them include:
South Africa, Nigeria, Zimbabwe, Malawi, Djibouti, Somalia, Algeria, Morocco, Tunisia, Liberia, Denmark, Norway, Wales, Finland, Sweden, Ireland...
These countries, as well as the rest that lack volcanoes are all countries that are not lying above collision or submersion lines between the tectonic plates, nor have a hot spot beneath them, which is where the volcanoes appear. The best known is the 'Ring of Fire' in the Pacific, where most of the active volcanoes are.</span>
Differences in eruptive forces cause a volcanic neck to form.
The correct answer is: A. eruptive forces
Good luck with your studies, I hope this helps~!
