What is the passage mainly about?

Câu hỏi: 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 35 to 42.
Do you think you're smarter than your parents, and grandparents? According to James Flynn, a professor at a New Zealand university, you might be. Over the course of the last century, IQ test scores of people in some countries have gotten increasingly better, on average, three points better for every decade that has passed. This trend of improving scores is known as "the Flynn effect" and scientists want to know what is behind it.
IQ tests and other similar tests are designed to measure general intelligence rather than knowledge. Flynn knew that intelligence is partly inherited from our parents and partly the result of our environment and experiences, but the improvement in test scores was happening too quickly to be explained by heredity. So what happened in the 20th century that led to higher test scores? Scientists have proposed several explanations for the Flynn effect. Some suggest that the improved test scores simply reflect an increased exposure to tests in general. Because we take so many tests, we learn test-taking techniques that help us perform better. Others have pointed to better nutrition, which results in babies being born larger, healthier, and with more brain development than in the past. Another possible explanation is a change in educational styles: children are encouraged to discover things for themselves rather than just memorizing information. This could prepare people to do the kind of problem-solving that intelligence tests require.
Flynn himself suggested that learning new technologies may have improved people's problem-solving skills. This may be true for the first decade of his tests, when IQ scores in many countries increased. However, in recent years, IQ test scores in some countries have begun to decline. Data from Norway, the Netherlands, Australia, and Great Britain have shown that as these countries become more and more modem, IQ scores have begun to drop.
While scientists aren't sure what's causing this decline, they think technology is dramatically changing the way that we learn and get information. For example, people are now able to access all kinds of information very easily using online resources like Google or Wikipedia. The danger is when they start to rely too much on these sources of information, and not do any thinking for themselves. Lifestyle changes that come with modem technology may also have a negative effect on intelligence, such as video games and television making people less social. So while the world may have gotten smarter over the 20th century, improving technology and changing lifestyles may soon reverse that trend.
What is the passage mainly about?
A. Factors affecting changes in people's IQ
B. Relationship between IQ and lifestyles
C. Influences of technology on IQ
D. How to improve IQ