Can someone help me with my work

What is the “narrow cell” in line 15 of “elegy written in a country churchyard”

1) earth's crust is made up of relatively rigid plates that ride atop earth's hot, semiliquid mantle. (2) the plates are called tectonic because they're in constant motion. (3) they can move because earth's mantle is a very hot and semiliquid fluid called magma. (4) volcanoes are a result of magma rising up or erupting through a plate, particularly where plate boundaries are moving against each other. (5) also, when plates slide against each other, causing friction along adjacent plate boundaries, earthquakes frequently occur. (6) therefore, we often find volcanoes and earthquakes along plate boundaries. (7) plates may also collide. (8) when that happens, mountain ranges are formed. (9) for example, the collision of the plate carrying the indian subcontinent created the himalayan mountains when it collided with the asian plate. which statement about this paragraph is accurate?

1. saved aronnax from drowning "an incident" 2. speed of the nautilus man-of-war 3. next to captain nemo conseil 4. electricity vigo bay 5. "a coral tomb" 20,000 leagues 6. the nautilus runs aground nemo's "thunderbolt" 7. episodes are connected by aronnax's quarters 8. captain nemo's "bank" cause 9. distance aronnax traveled on the nautilus "a fine death for a sailor" 10. captain nemo sinks for revenge 50 miles per hour