ATP在细胞中能够释放能量和储存能量，从其化学结构看原因是(　　)
①腺苷很容易吸收能量和释放能量
②第三个高能磷酸键很容易断裂和再结合
③第三个磷酸基团很容易从ATP上脱离，第二个高能磷酸键断裂，使ATP转变成ADP；反之，亦容易形成ATP
④ADP可以在酶作用下迅速与一分子磷酸结合，吸收能量形成第二个高能磷酸键，使ADP转变成ATP

阅读理解，根据短文选择正确的一项

    One day a policeman was walking in the park. He saw a man there. The man was holding a penguin（领着一个企鹅）. The man said to the policeman, “ I found this penguin this morning. What shall I do with it?”“Take it to the zoo,” said the policeman. The next day the policeman saw the man again. He was still holding the penguin. The policeman said, “Why didn't you take the penguin to the zoo?”“I did,” said the man. “I took him to the zoo yesterday. Today I'm taking him to the cinema.

已知等差数列{a_n}的前n项和为S_n，且S₂=10，S₅=55，则过点P（n，a_n）（n∈N^*）和Q（n+2，a_n+2）（n∈N^*）的直线的一个方向向量坐标可以是（　　）