制定美国1787年宪法的思想基础是源于下列哪位启蒙思想家的思想？（   ）

下列关于生物与环境的关系的叙述，不正确的是（    ）

已知关于x的一元二次方程x²﹣（k+3）x+3k=0．

（1）求证：不论k取何实数，该方程总有实数根．

（2）若等腰△ABC的一边长为2，另两边长恰好是方程的两个根，求△ABC的周长．

    Today is Sunday. The weather is fine. I go to the zoo with my parents. There are many animals at the zoo. Look！The pandas are eating bamboos(竹子) slowly. Two ducks are swimming in a lake. Two elephants are walking and a tiger is sleeping. I like monkeys best. They are jumping here and there. They like eating bananas. They are clever. Look! The bear is eating meat.
A. walking  B. swimming C. eating D. sleeping E. jumping

⑴ ____   

⑵  ____

⑶  ____

⑷  ____

⑸ ____

读我国的人口分布图回答：