题干

DNA分子片段复制的情况如图所示,图中a、b、c、d表示脱氧核苷酸链的片段.如果没有发生变异,下列说法错误的是()

A:b和c的碱基序列可以互补

B:a和c的碱基序列可以互补

C:a中 (A+T)(G+C) 的比值与b中 (A+T)(G+C) 的比值相同

D:a中 (A+G)(T+C) 的比值与d中 (A+G)(T+C) 的比值一般不相同

上一题 下一题 0.0难度 选择题 更新时间:2016-12-28 12:04:14

答案(点此获取答案解析)

B

同类题1

阅读下列短文,从每题所给的A、B、C、D四个选项中,选出最佳选项。

A Language Programme for Teenagers

Welcome to Teenagers Abroad! We invite you to join us on an amazing journey of language learning.

Our Courses

Regardless of your choice of course, you'll develop your language ability both quickly and effectively.

Our Standard Course guarantees a significant increase in your confidence in a foreign language, with focused teaching in all 4 skill areas----speaking, listening, reading and writing.

Our Intensive Course builds on our Standard Course, with 10 additional lessons per week, guaranteeing the fastest possible language learning (see table below).

Course Type

Days

Number of Lesson

 Course Timetable

Standard Course

Mon-Fri

20 lessons

9:30-12:30

Intensive Course

Mon-Fri

20 lessons

9:30-12:30

20 lessons

13:30-14:30

Evaluation

Student are placed into classes according to their current language skills. The majority of them take on online language test before starting their programme. However, if this is not available, students sit the exam on the first Monday of their course.

Learning materials are provided to students throughout their course, and there will never be more than 15 participants in each class.

Arrivals and Transfer

Our programme offers the full package—students are take good care of from the start through to the very end. They are collected from the airport upon arrival and brought to their accommodation in comfort. Werequire the student's full details at least 4 weeks in advance.

Meals/Allergies(过敏)/Special Dietary Requirements

Students are provided with breakfast, dinner and either a cooked or packed lunch (which consists of a sandwich, a drink and adessert). Snacks outside of meal times may be purchased by the student individually.

We ask that you let us know of any allergies or dietary requirements as well as information about any medicines you take. Depending on the type of allergies and/ or dietary requirements, an extra charge may be made for providing special food.