Coral island reading answer

In the rough and boundless sea, there is a colorful and colorful island-Coral Island.

② Most islands in the South China Sea are coral islands, among which Xisha Islands are the most famous. You can't help but be surprised when you know that these islands are actually caused by a small coral under the attack of wind and waves.

In the Forbidden City in Beijing, you can see some coral trees displayed as treasures. They are "apartments" built by corals with lime secreted by themselves. There are many small holes in the coral tree, and a coral once lived in each hole. They always live together in groups, forming a bush-like "apartment", but there are other shapes. Every time a new coral is born, they will build a new room, so with the proliferation of corals, coral trees will grow very tall and branch like trees. But the height will not exceed the water surface, because corals can only survive in water. When they are close to the water, the branches don't grow upward, but spread out like mushrooms. High-rise buildings rise from the ground, and coral "apartments" are fixed at the bottom of the sea. So corals can't move by themselves, so they can only live in a small "room" and stretch out a few tentacles to wait for food to be trapped. You may think that this "waiting for the rabbit" hunting method is too stupid, and you are worried that it will starve to death! But don't worry too much, because they are "everyone has food." In an apartment, all the corals are connected by a pipe. After any coral catches food and digests it, it will immediately share the food nutrition with you through this tube. There is little chance for a coral to catch food, and the cooperation of thousands of corals ensures that everyone has enough food to survive and reproduce.

(4) Although corals have settled down, they stop breeding new corals and become ovipositors when they develop to a certain extent. Eggs are taken to other places by seawater to develop and grow, and new "apartments" are built, thus forming a dense coral "forest" in the sea. This gap in the "forest" has become the habitat of many other marine animals.

⑤ With the passage of time, corals keep dying, but the "apartment" still exists. After death, the creatures in the "forest" will leave many calcareous hard shells, bones and other fragments, filling the gaps in the dense forest. The constantly emerging corals secrete a lot of calcium, which cements these things and gradually forms solid reefs and islands. Coral reefs are not formed slowly. On the Xisha Islands in China, an annual increase of three millimeters was observed.

⑥ The wind and waves did their best to destroy the coral work and broke many corals, but this did not stop the reef-building work. Stubborn corals constantly make up for the damage caused by the waves, and those broken corals are only used to fill the gaps in the "forest" and play a reinforcing role.

However, coral also has its "feminine taste". They are afraid of cold, dark and turbid seawater, so they can only survive in clear seawater with a temperature of not less than 20℃ and a depth of not more than 80 meters. The salt in seawater should not be too much or too little, and the salt content of about 2.7% is the most suitable for its growth; At the same time, it also needs a rocky seabed as the foundation of their "apartment". Therefore, coral reefs are mostly built around the islands in the mainland coast and ocean, mainly distributed between 30 north latitude and 30 south latitude. In the ocean, when the island on which coral trees live gradually sinks due to the influence of crustal movement, coral reefs continue to develop upwards due to the continuous growth of corals, forming a ring coral island. The center of the island is seawater, surrounded by dams made of coral reefs, with some gaps in the middle. Many coral islands in the ocean are in this form. If the bottom of the sea rises, it will become a solid coral island. The Xisha Islands in China are of this type, where the coral island is over12m above sea level.

(Author: Tao Shilong, abridged)

16.③ The meaning of "waiting for the rabbit" in paragraph 3 is (2 points).

17. The interpretation method used in the underlined sentence in paragraph (5) has the effect of (4 points).

18. Please fill in the appropriate words in the box below to indicate the formation process of coral island. (9 points)

19. One of the following statements is () (3 points)

A. Coral "apartments" are fixed on the sand at the bottom of the sea.

B. Corals have requirements on the temperature, depth and salt content of the seawater in which they live.

C. Coral islands have two forms: annular and solid, and Xisha Islands belong to solid coral islands.

D. Coral reefs mostly appear on the coast of the mainland and around islands in the ocean.

20. The expressive function of the word "general" added in paragraph 7 is (3 points).

Reference answer: This article is compiled and provided by "Writing Reading Answers Network for Primary and Secondary Schools".

16. Coral can't move freely by itself, living in its own room, sticking out several tentacles and waiting for food to trap itself. (2 points)

17. Examples (1 min) and columns (1 min) list examples of Xisha Islands in China. The specific data show that the formation speed of coral reefs is not slow. (2 points)

18. Coral-coral tree-coral forest (9 points)

19. Answer (3 points)

"General" means that corals should normally live in clear seawater with a temperature of not less than 20℃ and a depth of not more than 80 meters, but special circumstances are not excluded, which embodies the accurate science of descriptive terms. (3 points)