Many scientists believe that the current period of global warming is related to increased levels of
a. carbon dioxide in the earth's atmosphere.
b. nitrogen in the earth's atmosphere.
c. hydrogen in the outermost layer of the earth's atmosphere.
d. radon being released from the earth's soil.

the correct answers are:

a - pacific plate;

it is the biggest oceanic tectonic plate. surrounded on all sides by continental tectonic plates, it is submerging and gradually becoming smaller and smaller.

b - north american plate;

huge continental plate, occupying big portion of the northern hemisphere.

c -eurasian plate;

alongside the north american plate, it is one of the two dominant continental plates in the northern hemisphere.

d - indian plate;

a small continental plate, that has been part of gondwanaland initially, but after the break up of it, moved towards northeast and pushed into the eurasian plate that was once part of laurasia.

the answer will be b