Dissolved gasses under lots of pressure are being trapped in the magma, these expanding gases and steam are what causes it. Also, because of this heat getting more and more hotter, and the volume being lost due to the gasses over time the lava bursts out.
If you're asking for PLATO, I think the answer is "Four fused rings of carbon".
<span>The right anwer is (b). Indeed, some scientists consider viruses as non-living because viruses do not undergo mitosis, which is the usual way living cells reproduce themselves. On the contrary, viruses inoculate their genetic material in a host cell in such a way to force the cell to make a copy of the virus DNA, thus making more viruses, that then kill the host cell and disseminate themselves. In practice the viruses exploits the replication tools of the living cells to replicate themselves, since they lack the machinery and also they lack something resembling cell metabolism, i.e., they do not "eat" or "grow".</span>
