单选题 A water molecule consists of two hydrogen atoms attached to a single, larger oxygen atom. The angle between the two hydrogen atoms is 120 degrees--the same angle as the angles of a hexagon--which accounts for the characteristic six-sided structure of ice crystals.
2. The phrase accounts for in the passage means

【正确答案】 A
【答案解析】Accounts for means explains in this context. Clues: ... 120 degrees--the same angle as the angles of a hexagon--which the characteristic six-sided structure