After rereading the fragment with the comma splice, review the choices on the right and check the three correct ways to fix the
comma splice. We look at political documents, records, and historical agreements; they offer hints about life in the past. We look at political documents, they offer hints about life in the past, records, and historical agreements do too. We look at political documents, records, and historical agreements because they offer hints about life in the past. We look at political documents, records, and historical agreements. They offer hints about life in the past.
Even though you didn't give us the fragment with the comma slice, it isn't really necessary here as we can answer just based on these 4 options here. All options apart from the second one are correct - only the second option doesn't fix the mistake of the comma splice, whereas the other options do but connecting the sentences properly.
There are two ways in which scientists quantify the size of earthquakes: magnitude and intensity. You have probably heard of the Richter scale which is still used for small earthquakes, but most large earthquakes are now commonly reported using the moment magnitude scale
