How magma is generated in a subduction zone? How magma rising from a subduction zone causes a chain of volcanoes on the surface?

As a tectonic plate slides into the mantle, the hotter layer beneath Earth's crust, the heating releases fluids trapped in the plate. These fluids, such as seawater and carbon dioxide, rise into the upper plate and can partially melt the overlying crust, forming magma. As the magmas are lighter than the mantle and start to rise above the subduction zones to produce a linear belt of volcanoes parallel to the oceanic trench.

Explanation:

For example, carbon has six protons and is atomic number 6. Carbon occurs naturally in three isotopes: carbon 12, which has 6 neutrons (plus 6 protons equals 12), carbon 13, which has 7 neutrons, and carbon 14, which has 8 neutrons. All three have six protons, but their neutron numbers - 6, 7, and 8, respectively - all differ. This means that all three isotopes have different atomic masses (carbon-14 being the heaviest), but share the same atomic number (Z=6).

ANSWER : Carbon 14 (hope this helps!)