Hậu quả của đột biến mất đoạn lớn NST là

A. làm giảm cường độ biểu hiện của tính trạng.

B. ít ảnh hưởng tới sức sống của cơ thể.

C. làm giảm sức sống hoặc gây chết.

D. làm tăng cường độ biểu hiện của tính trạng.

Read the followingpassage carefully and then choose the best answer to each question.

Butterflies are among the most extensively studied insects - an estimated 90 percent of the world's species have scientific names. As a consequence, they are perhaps the best group of insects for examining patterns of terrestrial biotic diversity and distribution. Butterflies also have a favorable image with the general public. Hence, they are an excellent group for communicating information on science and conservation issues such as diversity.

Perhaps the aspect of butterfly diversity that has received the most attention over the past century is the striking difference in species richness between tropical and temperate regions.

For example, in 1875 one biologist pointed out the diversity of butterflies in the Amazon when he mentioned that about 700 species were found within an hour's walk, whereas the total number found on the British islands did not exceed 66, and the whole of Europe supported only 321. This early comparison of tropical and temperate butterfly richness has been well confirmed.

A general theory of diversity would have to predict not only this difference between temperate and tropical zones, but also patterns within each region, and how these patterns vary among different animal and plant groups. However, for butterflies, variation of species richness within temperate or tropical regions, rather man between them, is poorly understood. Indeed, comparisons of numbers of species among the Amazon basin, tropical Asia, and Africa are still mostly "personal communication" citations, even for vertebrates, In other words, unlike comparison between temperate and tropical areas, these patterns are still in the documentation phase.

In documenting geographical variation in butterfly diversity, some arbitrary, practical decisions are made. Diversity, number of species, and species richness are used synonymously; little is known about the evenness of butterfly distribution. The New World butterflies make up the preponderance of examples because they are the most familiar species. It is hoped that by focusing on them, the errors generated by imperfect and incomplete taxonomy will be minimized.

 The word consequence in the passage is closest in meaning to " x ".

A. explanation

B. result

C. analysis

D. Requirement

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 38 to 42.

  "Did you see that?" Joe said to his friend Bill. "You're a great shooter!"

Bill caught the basketball and bounced it before throwing it again. The ball flew into the net.

"Bill, you never miss!" Joe said admiringly.

"Unless I'm in a real game," Bill complained. "Then I miss all the time."

Joe knew that Bill was right. Bill performed much better when he was having fun with Joe in the school yard than he did when he was playing for the school team in front of a large crowd.

"Maybe you just need to practice more," Joe suggested.

"But I practice all the time with you!" Bill objected. He shook his head. "I just can't play well when people are watching me."

"You play well when I'm watching," Joe pointed out.

"That's because I've known you since we were five years old," Bill said with a smile. "I'm just not comfortable playing when other people are around."

Joe nodded and understood, but he also had an idea.

The next day Joe and Bill met in the school yard again to practice. After a few minutes, Joe excused himself.

"Practice without me," Joe said to his friend. "I'll be back in a minute."

Joe hurried through the school building, gathering together whomever he could find - two students, a math teacher, two secretaries, and a janitor. When Joe explained why he needed them, everyone was happy to help.

Joe reminded the group to stay quiet as they all went toward the school's basketball court. As Joe had hoped, Bill was still practicing basketball. He made five baskets in a row without noticing the silent people standing behind him.

"Hey, Bill!" Joe called out finally.

Bill turned. A look of surprise came over his face.

I just wanted to show you that you could play well with people watching you," Joe said. "Now you'll have nothing to worry about for the next game!"

What would be the best title for the story?

A. Practice Makes Perfect

B. Joe Joins the Team 

C. Bill Wins the Big Game

D. Bill's Basketball Problem

Chứng minh rằng dân số Nhật Bản đang già hóa.