Q1. What is the passage mainly about?

1. AHow to make cheese
2. BWhether drinking milk makes children taller
3. CWhy parents are tall
4. DHow much water children need

牛乳を飲むと背が伸びるのか、というテーマなので B。

Q2. According to the passage, where do most differences in height come from?

1. AGenes from our parents
2. BDrinking a lot of milk
3. CSleeping more
4. DPlaying sports

Most differences in height between people come from genes とあるので A。

Q3. In this passage, "it is not magic" means milk ...

1. Atastes very bad
2. Bcannot make you much taller by itself
3. Cis not safe to drink
4. Dis very expensive

効果は小さいという流れから、「牛乳だけで大きく背が伸びるわけではない」という意味なので B。

Q1. What did the review of controlled trials find?

1. ADairy had no effect on height at all.
2. BChildren given extra dairy grew several centimeters more each year.
3. CChildren given extra dairy grew slightly more each year.
4. DOnly adults became taller with milk.

grew slightly more each year ... less than one centimeter a year とあるので C。

Q2. Where is milk thought to help children's growth the most?

1. AIn countries where children already eat well
2. BIn poorer countries where children lack nutrients
3. CIn countries with many twins
4. DIn cold countries

milk helps most in poorer countries, where children often lack protein and other nutrients とあるので B。

Q3. What can we infer about the rise in Japanese people's height after the war?

1. AIt was caused mainly by changes in genes.
2. BIt was caused only by school milk.
3. CIt shows that height cannot change at all.
4. DIt was the result of many improvements in living conditions.

better food, hygiene and medical care overall, not milk alone とあり、生活環境全体の改善の結果と推測できるので D。

Q1. Which statement best expresses the main idea?

1. AMilk is the most important factor in children's height.
2. BMilk may help growth a little, but genes play a much larger role.
3. CMilk has no nutritional value for children.
4. DHeight depends only on the environment.

a grain of truth, but milk is far from the main factor、Genes matter far more とあるので B。

Q2. According to the passage, what does a heritability of about 80 percent mean?

1. A80 percent of each person's height comes from genes.
2. B80 percent of children will grow taller if they drink milk.
3. CIt describes differences in height within a certain population and environment.
4. DIt means environment has no effect on height.

Heritability describes differences within a particular population and environment, and it does not tell us how much of any one person's height is genetic とあるので C。A はよくある誤解。

Q3. Why might the link found in the American survey be misleading?

1. ABecause it may be influenced by family income or total energy intake
2. BBecause the children did not drink any milk
3. CBecause the studies were all done on twins
4. DBecause milk contains no protein

the survey link may be confounded by family income or total energy intake とあるので A。交絡（confounding）は研究の限界の典型。