Ở một loài thực vật, chiều cao của thân do hai cặp gen A, a và B, b phân li độc lập quy định; khi kiểu gen có cả hai alen A và alen B quy định kiểu hình thân cao, các kiểu gen còn lại quy định thân thấp. Cho hai cây có kiểu hình khác nhau (P) giao phấn với nhau, thu được F1 có kiểu hình phân li theo tỉ lệ 3 cây thân cao: 5 cây thân thấp. Cho tất cả các cây thân thấp ở F1 tạp giao với nhau thì ở đời sau thu được cây thân cao chiếm tỉ lệ là

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Một số câu hỏi khác có thể bạn quan tâm.

• Find a mistake in the four underlined parts of the sentence and correct it:

  Today, archaeological evidence reveals some of the mysteries that surrounded the history

  of the Wonders in centuries.

• Find a mistake in the four underlined parts of the sentence and correct it:

  The Statue of Zeus at Olympia was one of the Seven Wonder of the Ancient World.

• Find a mistake in the four underlined parts of the sentence and correct it:

  The circumstances of its eventual destructive are a source of debate that whether it was

  destroyed in a great fire in 475 or not.

• Find a mistake in the four underlined parts of the sentence and correct it:

  More than 80% of home pages in the Web are in English, while the next greatest, German,

  has only 4.5% and Japanese 3.1%.

• Find a mistake in the four underlined parts of the sentence and correct it:

  The number of people with English as a second language are overtaking the number of

  people for whom the language is their mother tongue.
  
  

• Find a mistake in the four underlined parts of the sentence and correct it:

  The most distinguishing differences between American English and British English is in

  pronunciation and vocabulary.

• Find a mistake in the four underlined parts of the sentence and correct it:

  There are wide varieties of American dialects, some of that appear to be diverging markedly from others.

• Find a mistake in the four underlined parts of the sentence and correct it:

  The use of English ethnic dialects vary from region to region and social group to social group.

• Choose the word that has the underlined part pronounced differently from the rest:

  follow                  job                      geography                     develop

• Choose the word that has the underlined part pronounced differently from the rest:

  awful                   quality                        corner                      fourteen