Reading: Sentence Completion: Question 3

More than ninety-five percent of the world's international data traffic, everything from video calls to financial transactions, travels not through satellites, as many people assume, but through a network of submarine fibre-optic cables laid along the ocean floor. A single modern cable typically contains fewer than a dozen fibre-optic pairs, hair-thin strands of glass along which data travels as pulses of laser light rather than as an electrical signal, allowing capacity and speed far beyond what a satellite link, hampered by physical distance and the delay it introduces, can achieve.

Laying a submarine cable begins long before any ship reaches open water. Marine surveyors first spend months studying detailed seabed maps to plot a route that avoids fishing grounds, shipwrecks and, wherever possible, geologically unstable regions prone to underwater landslides. Specialised cable-laying vessels then feed the cable from enormous rotating drums on deck, lowering it to the seabed at a controlled rate; in shallower coastal waters, a plough towed behind the ship buries the cable roughly one to two metres beneath the seabed to protect it from fishing trawlers and ship anchors, the two most common causes of cable damage.

Despite this protection, faults remain a routine hazard: on average, a submarine cable somewhere in the world is damaged roughly every three days, most often by a dragged anchor or a trawler's fishing gear rather than by a shark bite, a cause that generates disproportionate media attention despite being genuinely rare. When a fault is detected, a repair ship sails to the affected coordinates, grapples the cable from the seabed using a hook lowered on a line, hauls the damaged section to the surface, and splices in a new length before lowering the repaired cable back down, a process that can take one to three weeks depending on weather and water depth.

Because so few cables exist relative to the volume of traffic they carry, a handful of narrow maritime corridors, among them the Luzon Strait and the Strait of Malacca, have become chokepoints where a large share of intercontinental data physically converges, meaning that a single incident in one of these corridors can measurably slow internet traffic across entire continents.

Complete the sentences below. Choose NO MORE THAN TWO WORDS from the passage for each answer.

1. More than ____________________ of the world's international data traffic travels through submarine cables rather than satellites.
2. Inside a fibre-optic pair, data travels as pulses of ____________________ rather than as an electrical signal.
3. Before a cable is laid, surveyors study seabed maps to avoid fishing grounds, shipwrecks and areas prone to underwater ____________________.
4. In shallow coastal waters, a plough buries the cable to protect it from fishing trawlers and ____________________.
5. On average, a submarine cable somewhere in the world is damaged roughly every ____________________.
6. Most cable faults are caused by dragged anchors or fishing gear rather than by a ____________________, a cause that receives disproportionate media attention.
7. After hauling the damaged section to the surface, a repair ship ____________________ in a new length of cable.
8. A cable repair can take one to three weeks depending on weather and ____________________.