If earth was not a connecting system then the heat from its interior wouldn’t have effect on the tectonic plate at all. The heat from the interior causes the tectonic plates to shift, which effects the oceans sea floor and does cause volcanos to be created.
What do you mean about 'Elective courses'? Is it the courses the students chose?
If then, say we have the right to learn what we want.
They are helping verbs. Your helping verbs are the following:
am been may
is can might
are could must
was shall
were should
be will
being would
