Đáp án

Manatees

Manatees, also known as sea cows, are aquatic mammals that belong to a group of animals called Sirenia. This group also contains dugongs. Dugongs and manatees look quite alike – they are similar in size, colour and shape, and both have flexible flippers for forelimbs. However, the manatee has a broad, rounded tail, whereas the dugong’s is fluked, like that of a whale. (Q1) There are three species of manatees: the West Indian manatee (Trichechus manatus), the African manatee (Trichechus senegalensis) and the Amazonian manatee (Trichechus inunguis).

Unlike most mammals, manatees have only six bones in their neck – most others, including humans and giraffes, have seven. This short neck allows a manatee to move its head up and down, but not side to side. To see something on its left or its right, a manatee must turn its entire body, steering with its flippers. (Q2) Manatees have pectoral flippers but no back limbs, only a tail for propulsion. They do have pelvic bones, however a leftover from their evolution from a four-legged to a fully aquatic animal. Manatees share some visual similarities to elephants. Like elephants, manatees have thick, wrinkled skin. They also have some hairs covering their bodies which help them sense vibrations in the water around them. (Q3)

Seagrasses and other marine plants make up most of a manatee’s diet. (Q4) Manatees spend about eight hours each day grazing and uprooting plants. They eat up to 15% of their weight in food each day. African manatees are omnivorous – studies have shown that molluscs and fish make up a small part of their diets. West Indian and Amazonian manatees are both herbivores.

Manatees’ teeth are all molars – flat, rounded teeth for grinding food. Due to manatees’ abrasive aquatic plant diet, these teeth get worn down and they eventually fall out, so they continually grow new teeth that get pushed forward to replace the ones they lose. Instead of having incisors to grasp their food, manatees have lips which function like a pair of hands to help tear food away from the seafloor. (Q5)

Manatees are fully aquatic, but as mammals, they need to come up to the surface to breathe. When awake, they typically surface every two to four minutes, but they can hold their breath for much longer. Adult manatees sleep underwater for 10-12 hours a day, but they come up for air every 15-20 minutes. Active manatees need to breathe more frequently. It’s thought that manatees use their muscular diaphragm and breathing to adjust their buoyancy. They may use diaphragm contractions to compress and store gas in folds in their large intestine to help them float. (Q6)

The West Indian manatee reaches about 3.5 metres long and weighs on average around 500 kilograms. It moves between fresh water and salt water, taking advantage of coastal mangroves and coral reefs, rivers, lakes and inland lagoons. (Q7) There are two subspecies of West Indian manatee: the Antillean manatee is found in waters from the Bahamas to Brazil, whereas the Florida manatee is found in US waters, although some individuals have been recorded in the Bahamas. In winter, the Florida manatee is typically restricted to Florida. When the ambient water temperature drops below 20°C, it takes refuge in naturally and artificially warmed water, such as at the warm-water outfalls from powerplants. (Q8)

The African manatee is also about 3.5 metres long and found in the sea along the west coast of Africa, from Mauritania down to Angola. The species also makes use of rivers, with the mammals seen in landlocked countries such as Mali and Niger. (Q9)

The Amazonian manatee is the smallest species, though it is still a big animal. It grows to about 2.5 metres long and 350 kilograms. Amazonian manatees favour calm, shallow waters that are above 23°C. This species is found in fresh water in the Amazon Basin in Brazil, as well as in Colombia, Ecuador and Peru.

All three manatee species are endangered or at a heightened risk of extinction. The African manatee and Amazonian manatee are both listed as Vulnerable by the International Union for Conservation of Nature (IUCN). It is estimated that 140,000 Amazonian manatees were killed between 1935 and 1954 for their meat, fat and skin, with the latter used to make leather. In more recent years, African manatee decline has been tied to incidental capture in fishing nets and hunting. Manatee hunting is now illegal in every country the African species is found in.

The two subspecies of West Indian manatee are listed as Endangered by the IUCN. Both are also expected to undergo a decline of 20% over the next 40 years. (Q11) A review of almost 1,800 cases of entanglement in fishing nets and of plastic consumption among marine mammals in US waters from 2009 to 2020 found that at least 700 cases involved manatees. (Q12) The chief cause of death in Florida manatees is boat strikes. However, laws in certain parts of Florida now limit boat speeds during winter, allowing slow-moving manatees more time to respond. (Q13)

 

Questions 1–6

Complete the notes below.

Choose ONE WORD AND/OR A NUMBER from the passage for each answer.

Manatees Appearance

Look similar to dugongs, but with a differently shaped 1 ___________

Movement

• Have fewer neck bones than most mammals
• Need to use their 2 ___________ to help to turn their bodies around in order to look sideways
• Sense vibrations in the water by means of 3 ___________ on their skin

Feeding

• Eat mainly aquatic vegetation, such as 4 ___________
• Grasp and pull up plants with their 5 ___________

Breathing

• Come to the surface for air every 2–4 minutes when awake and every 15–20 while sleeping
• May regulate the 6 ___________ of their bodies by using muscles of diaphragm to store air internally

 

Questions 7–13: Do the following statements agree with the information given in Reading Passage 1?

TRUE if the statement agrees with the information

FALSE if the statement contradicts the information

NOT GIVEN if there is no information on this

7. West Indian manatees can be found in a variety of different aquatic habitats.
8. The Florida manatee lives in warmer waters than the Antillean manatee.
9. The African manatee’s range is limited to coastal waters between the West African countries of Mauritania and Angola.
10. The extent of the loss of Amazonian manatees in the mid-twentieth century was only revealed many years later.
11. It is predicted that West Indian manatee populations will fall in the coming decades.
12. The risk to manatees from entanglement and plastic consumption increased significantly in the period 2009–2020.
13. There is some legislation in place which aims to reduce the likelihood of boat strikes on manatees in Florida.

 

Giải thích chi tiết

Câu hỏi	Đáp án	Từ khóa  trong câu hỏi	Từ đồng nghĩa  trong bài	Giải thích
1	tail	Look similar to dugongs, but with a differently shaped ___________	Dugongs and manatees look quite alike – they are similar in size, colour and shape, and both have flexible flippers for forelimbs. However, the manatee has a broad, rounded tail, whereas the dugong’s is fluked, like that of a whale.	Dugongs và manatees trông khá giống nhau – chúng có kích thước, màu sắc và hình dạng tương tự nhau, và cả hai đều có vây trước linh hoạt. Tuy nhiên, manatee có đuôi rộng và tròn, trong khi đuôi của dugong lại chia thùy, giống như đuôi cá voi.
2	flippers	Need to use their ___________ to help to turn their bodies around in order to look sideways	To see something on its left or its right, a manatee must turn its entire body, steering with its flippers.	Để nhìn thấy vật gì đó ở bên trái hoặc bên phải, manatee phải xoay toàn bộ cơ thể, điều hướng bằng các vây trước của mình.
3	hairs	Sense vibrations in the water by means of ___________ on their skin	They also have some hairs covering their bodies which help them sense vibrations in the water around them.	Chúng cũng có một số loại lông bao phủ cơ thể, giúp chúng cảm nhận được những rung động trong làn nước xung quanh.
4	seagrasses	Eat mainly aquatic vegetation, such as ___________	Seagrasses and other marine plants make up most of a manatee’s diet.	Cỏ biển và các loại thực vật biển khác chiếm phần lớn trong chế độ ăn của manatee.
5	lips	Grasp and pull up plants with their ___________	Instead of having incisors to grasp their food, manatees have lips which function like a pair of hands to help tear food away from the seafloor.	Thay vì có răng cửa để gặm thức ăn, manatee có đôi môi hoạt động như một đôi bàn tay, giúp chúng xé thức ăn ra khỏi đáy biển.
6	buoyancy	May regulate the ___________ of their bodies by using muscles of diaphragm to store air internally	It’s thought that manatees use their muscular diaphragm and breathing to adjust their buoyancy. They may use diaphragm contractions to compress and store gas in folds in their large intestine to help them float.	Người ta cho rằng manatee sử dụng cơ hoành và quá trình hô hấp để điều chỉnh độ nổi của cơ thể. Chúng có thể co thắt cơ hoành để nén và tích trữ khí trong các nếp gấp của ruột già, giúp cơ thể nổi lên trong nước.
7	TRUE	West Indian manatees can be found in a variety of different aquatic habitats.	The West Indian manatee … It moves between fresh water and salt water, taking advantage of coastal mangroves and coral reefs, rivers, lakes and inland lagoons.	Loài manatee Tây Ấn… Chúng di chuyển giữa nước ngọt và nước mặn, tận dụng các khu rừng ngập mặn ven biển và các rạn san hô, sông ngòi, hồ và đầm phá nội địa.
8	NOT GIVEN	The Florida manatee lives in warmer waters than the Antillean manatee.	… the Antillean manatee is found in waters from the Bahamas to Brazil, whereas the Florida manatee is found in US waters, … In winter, the Florida manatee is typically restricted to Florida. When the ambient water temperature drops below 20°C, it takes refuge in naturally and artificially warmed water, such as at the warm-water outfalls from powerplants.	Ta chỉ biết loài Florida manatee sống trong những vùng nước ấm tự nhiên hoặc nhân tạo chứ ko thấy so sánh giữa nhiệt độ nước nơi hai loài này sinh sống.
9	FALSE	The African manatee’s range is limited to coastal waters between the West African countries of Mauritania and Angola.	The African manatee is also about 3.5 metres long and found in the sea along the west coast of Africa, from Mauritania down to Angola. The species also makes use of rivers, with the mammals seen in landlocked countries such as Mali and Niger.	Loài manatee châu Phi cũng dài khoảng 3,5 mét và được tìm thấy ở vùng biển dọc theo bờ biển phía tây châu Phi, từ Mauritania kéo dài xuống Angola. Loài này cũng sinh sống ở các con sông, và đã được nhìn thấy tại những quốc gia không giáp biển như Mali và Niger. ⇒ Mâu thuẫn với câu hỏi.
10	NOT GIVEN	The extent of the loss of Amazonian manatees in the mid-twentieth century was only revealed many years later.	The Amazonian manatee is …	Ta không tìm thấy thời điểm người ta tiết lộ sự biến mất của loài Amazonian manatee.
11	TRUE	It is predicted that West Indian manatee populations will fall in the coming decades.	The two subspecies of West Indian manatee are listed as Endangered by the IUCN. Both are also expected to undergo a decline of 20% over the next 40 years.	Hai phân loài của manatee Tây Ấn được tổ chức IUCN xếp vào danh sách loài nguy cấp. Cả hai đều được dự đoán sẽ suy giảm 20% trong vòng 40 năm tới.
12	NOT GIVEN	The risk to manatees from entanglement and plastic consumption increased significantly in the period 2009–2020.	A review of almost 1,800 cases of entanglement in fishing nets and of plastic consumption among marine mammals in US waters from 2009 to 2020 found that at least 700 cases involved manatees.	Ta chỉ biết trong giai đoạn này có 700 trường hợp manatee bị mắc vào lưới đánh cá hoặc ăn phải rác thải nhựa chứ không có thông tin liệu những mối nguy này đã tăng lên hay không.
13	TRUE	There is some legislation in place which aims to reduce the likelihood of boat strikes on manatees in Florida.	The chief cause of death in Florida manatees is boat strikes. However, laws in certain parts of Florida now limit boat speeds during winter, allowing slow-moving manatees more time to respond.	Nguyên nhân tử vong chính của manatee ở Florida là do va chạm với thuyền. Tuy nhiên, các luật pháp tại một số khu vực ở Florida hiện nay đã giới hạn tốc độ thuyền vào mùa đông, cho phép những con manatee chậm chạp có thêm thời gian để phản ứng.