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2018 ‫מועד קיץ‬ - 49 - ‫ פרק שנ י‬- ‫ אנגלית‬

Text II (Questions 18-22)

(1) They may look like beautiful rock formations, but coral reefs are actually made up
of countless tiny marine animals. Usually found in shallow tropical waters, coral reefs
are home to a fourth of the world's marine species. A major threat to coral is turtleweed,
a kind of seaweed that releases toxic chemicals as it nears the reefs.

(5) Understandably, most fish keep their distance from turtleweed. However, scientists
have observed that two types of fish that live in coral reefs – the broad-barred goby and
the redhead goby – actually attack turtleweed. Danielle Dixson and Mark Hay of the
Georgia Institute of Technology (GIT) conducted experiments to investigate this
phenomenon. First they placed both types of gobies together with turtleweed in a tank

(10) and saw that the fish ignored the seaweed. They then added a common type of coral –
staghorn coral – to the tank, and the gobies went on the offensive.

The scientists discovered that when turtleweed approaches staghorn corals, the
corals release an odor-producing chemical. The odor acts as a signal to the gobies,
causing them to rush to the scene and destroy the turtleweed. In doing so, the fish

(15) ensure the continued existence of their own habitat and that of hundreds of other reef-
dwelling creatures. The broad-barred goby, which actually swallows the turtleweed,
gains even more: the poison that it absorbs deters predators from hunting it.

Coral reef biologist Nancy Knowlton of the Smithsonian National Museum of
Natural History was impressed by the GIT study and what it reveals about the intricate

(20) interactions among living things: "Who would have thought that such a small,
seemingly insignificant fish would play such a large role in protecting coral reefs?"

Questions

18. An appropriate title for this text would be -

(1) The Broad-Barred Goby and the Redhead Goby: A Comparison
(2) Staghorn Coral and Gobies: Protecting the Coral Reefs
(3) Coral Reefs: More Than Beautiful Rock Formations
(4) Dixson and Hay: Saving the World's Coral Reefs

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