A:I was short at that time.
B:I had short hair then.
C:I was five years old then.
下列图案既是轴对称图形,又是中心对称图形的是 ( )
到了秋天,山上许多的植物会由绿转黄,原因之一是叶片的细胞中存在花青素,你认为花青素是存在于叶片细胞的()