Numerical answer
Five sentences, numbered 1 to 5, are given below. Four of them can be arranged into a coherent paragraph; one does not fit. Key in the number of the sentence that does NOT fit.
1. Coral reefs are often called the rainforests of the sea because of the sheer density of species they support relative to the area they occupy.
2. A single reef system can host thousands of fish species alongside countless invertebrates, all within a structure built by the coral polyps themselves over centuries.
3. Rainforests, by contrast, generate roughly forty percent of the oxygen present in Earth's atmosphere through continuous photosynthesis.
4. This biodiversity arises because the reef's physical complexity creates an enormous number of micro-habitats, from crevices to open sand, each suited to different species.
5. Coral bleaching, triggered by sustained increases in water temperature, strips this structure of the algae that give it both colour and much of its energy supply.
1. Coral reefs are often called the rainforests of the sea because of the sheer density of species they support relative to the area they occupy.
2. A single reef system can host thousands of fish species alongside countless invertebrates, all within a structure built by the coral polyps themselves over centuries.
3. Rainforests, by contrast, generate roughly forty percent of the oxygen present in Earth's atmosphere through continuous photosynthesis.
4. This biodiversity arises because the reef's physical complexity creates an enormous number of micro-habitats, from crevices to open sand, each suited to different species.
5. Coral bleaching, triggered by sustained increases in water temperature, strips this structure of the algae that give it both colour and much of its energy supply.
Show answer and solution
Answer: 3
Sentences 1, 2, 4 and 5 form a coherent account of coral reefs: why they're compared to rainforests (1), what that density looks like (2), why it arises (4), and a threat to it (5). Sentence 3 shifts the topic to a fact about rainforests' oxygen production — a tangential comparison point that does not develop the paragraph's actual subject, the coral reef, and breaks the otherwise tight thematic chain.
Saved on this device. Sign in or create a free account to keep it on every device.