题目内容：
Why do some scientists study how plants convert sunlight, carbon dioxide, and water into sugars and starches?
A．Because they want algae to produce sugars and starches. B．Because they want green plants to become a new source of energy.
C．Because they want to turn plant sugars to a new form of energy.
D．Because they want to make photosynthesis more efficient.
参考答案：
答案解析：