Danh sách câu hỏi ( Có 2,390,622 câu hỏi trên 47,813 trang )

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 31 to 35. Korea's recent unveiling of the world's first cloned dog was welcomed by King Chow, assistant professor of biotechnology at the Hong Kong University of Science and Technology, but he also warned that we need to be on guard against possible reproductive cloning. Professor Chow went on to explain that, “The development of the technology is a good thing in itself but how we monitor it and who we allow to use it will be of great importance”. Professor Chow is one of many academics who feel that a clear line must be drawn between reproductive cloning and therapeutic cloning. Therapeutic cloning involves the use of embryonic stem cells to develop human cells or organs that can be used to cure diseases such as Parkinson's and diabetes. People in wheelchairs may be able to walk again thanks to this technology as scientists believe that they can clone new cells to repair back and neck injuries. Reproductive cloning involves implanting a cloned embryo into a uterus in the hope of producing a healthy foetus. A company called Clonaid claims to have successfully cloned thirteen human babies. They say that all of the babies are healthy and are in various locations, including Hong Kong, UK, Spain and Brazil. Clonaid states that they are using human cloning to assist infertile couples, homosexual couples and families who have lost a beloved relative. The same technology can be used for animal cloning. If endangered species such as the giant panda and Sumatran tiger could be cloned, they could be saved from extinction. Livestock such as cows could also be cloned to allow farmers to reproduce cattle that produce the best meat and most milk. This could greatly help developing countries where cows produce significantly less meat and milk. What does the passage mainly discuss?

Xem chi tiết 1.2 K lượt xem 4 năm trước

Ở một loài động vật, tính trạng màu mắt do 1 gen gồm 4 alen nằm trên nhiễm sắc thể thường chi phối. Tiến hành các phép lai thu được kết quả như mô tả: Phép lai 1: Cá thể đực mắt đỏ lai với cá thể cái mắt nâu (P), thu được F1 có kiểu hình phân li theo tỉ lệ 1 cá thể mắt đỏ: 2 cá thể mắt nâu: 1 cá thể mắt vàng. Phép lai 2: Cá thể đực mắt vàng lai với cá thể cái mắt vàng (P), thu được F1 có kiểu hình phân li theo tỉ lệ 3 cá thể mắt vàng: 1 cá thể mắt trắng. Cho biết không xảy ra đột biến. Về mặt lí thuyết, có bao nhiêu phát biểu sau đây chính xác? I. Ở loài này, kiểu hình mắt đỏ được chi phối bởi nhiều loại kiểu gen nhất. II. Ở loài này, cho cá thể đực mắt nâu giao phối với các cá thể cái có kiểu hình khác, có tối đa 6 phép lai đều thu được đời con gồm toàn cá thể mắt nâu. III. Thế hệ lai F1 của phép lai 1 có các kiểu gen phân li theo tỉ lệ 1 : 2 : 1. IV. Cho cá thể đực mắt đỏ ở P của phép lai 1 giao phối với cá thể cái mắt vàng ở P của phép lai 2, có thể thu được đời con có kiểu hình phân li theo tỉ lệ 1 : 2 : 1.

Xem chi tiết 375 lượt xem 3 năm trước

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 26 to 30.    Dressing up in costumes and trick-or-treating are popular Halloween activities, but few probably (26) ______ these lighthearted fall traditions with their origins in Samhain, a three-day ancient Celtic pagan festival. For the Celts, who lived during the Iron Age in what is now Ireland, Scotland, the U.K. and (27) ______ parts of Northern Europe, Samhain (meaning literally, in modern Irish, “summer's end”) marked the end of summer and kicked off the Celtic new year. Ushering in a new year signaled a time of both death and rebirth, something that was doubly symbolic because it (28) ______ with the end of a bountiful harvest season and the beginning of a cold and dark winter season that would present plenty of challenges.    Eventually, Halloween became more popular in secular culture than All Saints' Day. The pagan-turned- Christian practices of dressing up in costumes, playing pranks and handing out offerings have evolved into popular traditions even for those (29) ______ may not believe in otherworldly spirits or saints. (30) ______, whether Halloween celebrants know it or not, they’re following the legacy of the ancient Celts who, with the festival of Samhain, celebrated the inevitability of death and rebirth.

Xem chi tiết 2.4 K lượt xem 3 năm trước