Cho cà chua quả tròn thụ phấn với quả bầu dục thu được đời con toàn quả tròn. Nếu chỉ chọn cây cà chua quả bầu dục cho lai với nhau theo dõi liên tục qua nhiều đời thấy đời con chỉ xuất hiện quả cà chua bầu dục. a, thí nghiệm trên nghiên cứu sự di truyền của loại tính trạng nào? b, kể tên tính trạng cà chua được miêu tả trong bài. c, chỉ ra cặp tính trạng tương phản. d, cây cà chua nào được gọi là thuần chủng, cây nào là không thuần chủng. e, sử dụng các ký hiệu thích hợp cho trường hợp trên.

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Read the following passage and mark the letter A, B, C, or D to indicate the correct word or phrase that best fits each of the numbered blanks. Would you like to learn to rock climb? Or spend time working at an animal sanctuary? That's (23) ____ Andrea Black and Jenny Smith are doing as part of their Duke of Edinburgh Award programme. The award encourages young people to do (24) ____ cultural, social and adventurous activities in their free time. The Queen's husband, the Duke of Edinburgh, started the award in 1956. He started it (25) ____ he wanted young people to learn to help themselves and other people.The award is for people aged 14-25, and there are three levels: Bronze, for those aged 14 or over, Silver for over 15s, and Gold for over 16s. You have to complete four activities to (26) ____ the award: - go on an expedition (e.g. hiking, kayaking or climbing) - learn a new practical or social skill (anything from painting to podcasting!) - take (27) ____ a physical challenge (e.g. learn or improve at a sport) - do voluntary work helping people or the environment (e.g. work with disabled or elderly people, or (28) ______ money for a charity). Young people usually do the award at a Duke of Edinburgh club at their school or at a local youth group. They (29) ____ what they are going to do, and write a plan. It usually takes (30) ____ one and three years to finish an award. 23. A. what B. why C. which D. when 24. A. excited B. exciting C. excitement D. excite 25. A. therefore B. but C. because D. if 26. A. compete B. accept C. realize D. achieve 27. A. on B. in C. away D. after 28. A. lift B. increase C. raise D. advance 29. A. decide B. are deciding C. decided D. had decided 30. A. from B. in C. during D. between