Have you ever seen a horse with toes? Millions of years ago, horses had many toes. They had four toes on each front foot. They had three toes on each back foot. The horses were no bigger than the cats. These small horses lived in the forest. The toes helped the horses run on the soft, wet ground.

    At first, it was very hot in the forest. But the weather changed. It became very cold. Many trees could not live in cold weather. The trees died and fell. Open fields took the place of forests. The sun made the ground dry and hard.

    Horses began to change, too. They began to get bigger. This took a long time. On the dry, hard land, horses needed only their middle toes for running. Their middle toes became hard. After a long time, horses had only one hard toe on each foot. Now we call this hard toe a hoof(蹄子).

由于博览会可以“开风气而劝工商”，1908年，两江总督端方奏请政府创办展览会；1910年，中国人首次在南京创办了博览会。被称为“南洋劝业会”。这反映了当时中国人创办博览会的主要目的是

下列关于生态系统各成分功能的叙述中，不正确的是（  ）

2016年3月16日，第十二届全国人民代表大会第四次会议表决通过《中华人民共和国慈善法》，该法将于2016年9月1日起实施。据此回答小题。