Ⅰ
１ 協力の基礎となる抽象的概念を子供が理解し始めるのは何歳かを特定することによって。（40字）
２ Trina Hinkley－C Ulrike Kachel－A Mike Nagel－B Margarita Svetlova－A
３ ①－B ②－C ③－B
４ P5
５ ７２人の３歳児を実験前に妨害するよう指示された子供とペアにし，協力して作業をしている時の妨害行為に対する反応を観察する。（69字）
［別解］ ７２人の３歳児を実験前に作業の邪魔をするよう指示された子供とペアにし，事前に協力に合意した作業中の妨害行為に対する観察対象の反応を観察する。（70字）
６ 観察対象の子供はどんな理由であれ失敗にいら立ったが，パートナーが利己的な行動をしたと思った時により強い，怒りの反応を示した。（62字）
Ⅱ
１ ある科学者のグループがこのような異なる形がどのように表れるのかという謎を解明することに前進したかもしれない。
２ イ－C ロ－D ハ－B ニ－A
３ B
４ flying ability
５ 飛行に適した空気抵抗のない流線型の体にするため卵の幅が制限されるが，黄身と白身を最大限に含む体積を卵に持たせるにはしずく型［涙の形／楕円形］が最適だから。（68字）
６ The shapes of eggs depend on where their nest is and how many eggs there are in it.
Ⅲ
１ A → doing B → create F → discouraged G → Basing
２ ①－A ②－B ③－D ④－C
３ C，D
４ (I agree with the idea that it is good for a person to have a job related to their hobby.) The most important thing is whether you can enjoy working or not. People spend most of their time working, so the more enjoyable you find your work, the more pleasant a life you can lead. (35 words)
(I disagree with the idea that it is good for a person to have a job related to their hobby.) It would be good to make a living from what you like, but sometimes you just need to get away from it all. At such times, doing anything enjoyable other than work can help you feel relaxed. (37 words)
Ⅳ
(The table shows the percentage for Internet users who used social networking services (SNS) by age between 2005 and 2015. Firstly,) from 2005 to 2015, the number of SNS users increased in every age group. Secondly, in 2010, more than half of those in the younger two age groups used SNSs, while less than half of those in the older two groups did. Lastly, the percentage of those 65 and older increased gradually, by 20 points in the first five years and by 30 points in the last five.
