Most birds prefer a warmer southern climate during winter but migrate north in summer to nest. Scientists have proposed several explanations for why these birds don't stay in the warmer south. One possibility is that in summer the north has a huge insect supply, which provides a plentiful food source for young birds. Another is that the higher northern latitude provides longer daylight hours. Parents can therefore take advantage of additional hours to find food for their young.

Question

Most birds prefer a warmer southern climate during winter but migrate north in summer to nest. Scientists have proposed several explanations for why these birds don't stay in the warmer south. One possibility is that in summer the north has a huge insect supply, which provides a plentiful food source for young birds. Another is that the higher northern latitude provides longer daylight hours. Parents can therefore take advantage of additional hours to find food for their young.
What purpose does the second sentence of the passage serve?
1It indicates the passage will go on to list some explanations for bird migration.
2 It uses repetition to emphasize the idea that birds prefer a warmer climate.
3 It provides a possible explanation for the phenomenon of bird migration.

GPT 3.5 · Answer

1It indicates the passage will go on to list some explanations for bird migration.