Q1. What is the passage mainly about?

1. AHow to run faster
2. BWhether fitness and intelligence are connected
3. CWhy Swedish men are strong
4. DHow to get better grades in math

体力（スタミナ）と知能テストの点の関係を調べた研究の話なので B。

Q2. What did NOT matter for the test scores?

1. AStamina
2. BExercising for a long time
3. CStrong muscles
4. DHeart and lung fitness

But strong muscles did not matter. とあるので C。

Q3. In this passage, "stamina" means ...

1. Athe power to keep moving for a long time
2. Bthe ability to run very fast for a short time
3. Ca kind of school test
4. Dthe size of your muscles

直後の who could exercise for a long time が言い換えになっているので A。

Q1. What is the main idea of the passage?

1. AFast runners are always smarter.
2. BFitness, especially endurance, is linked to test scores, but exercise has not clearly been shown to raise grades.
3. CMuscle strength is the key to intelligence.
4. DExercise lowers math scores.

持久力とテストの点に関係がある一方、運動で学校の成績全体が上がるかは判断しにくいと述べているので B。

Q2. According to the 2019 review, in which subject was there strong evidence of a positive effect?

1. AEnglish
2. BScience
3. CHistory
4. DMath

For math, though, there was strong evidence of a positive effect とあるので D。

Q3. Why does the writer say "this kind of study only shows a link"?

1. ATo warn that fitness may not be the cause of higher scores
2. BTo show that the Swedish study was a mistake
3. CTo prove that exercise causes intelligence
4. DTo explain how the bike test works

直後に It does not show that exercise makes people smarter とあり、関係があっても運動が点数を上げた原因とは言えないという注意なので A。

Q1. What is the passage mainly about?

1. AHow to train for a marathon
2. BWhy twins have the same intelligence
3. CEvidence linking fitness and intelligence, and its limits
4. DHow the Swedish military chooses soldiers

持久力と知能の関連を示す研究と、観察研究であることなどの限界、介入研究の結果を論じているので C。

Q2. What did the comparison within identical twin pairs suggest?

1. AThe link depends mainly on genes.
2. BTwins always have the same fitness.
3. CMuscle strength matters more than endurance.
4. DThe link is largely explained by individual environment.

So the link seems to come mainly from individual environment, not genes とあるので D。

Q3. Which limitation of the Swedish study does the author mention?

1. AIt included too few people.
2. BIt studied only women.
3. CIt was observational, so it could not prove cause and effect.
4. DIt measured only sprinting speed.

It was also observational. のあとに、睡眠のような習慣が両方を高めているかもしれないと述べているので C。対象は男性のみ、測ったのは持久力。