But each one of these is a different age, and if we can find out how old they are and then we can measure those chemical signals, this helps us to find out what's been going on in the ocean in the past.
それぞれ年齢が異なり もしも年齢が分かれば 化学信号の測定が可能で 過去に海で何が起きていたのかを 調査するのに役立ちます