1863年是闰年还是平年

United States
Thanksgiving Day was originally observed on various dates decided by each state.After the independence of the United States,It became a statutory holiday declared by President Lincoln in 1863.It was not until 1941 that the observation date was fixed on the fourth Thursday in November by a bill of Congress.
Canada
In 1879,the Canadian Paliament proclaimed Thanksgiving Day to be a national holiday and to be observed on 6 November.The date was changed several times thereafter.It was not until January 31,1957 that the Paliament declared Thanksgiving Day to be celebrated on the second Monday in October to thank almighty God for blessing Canada and giving good harvest.

解题思路：据图在1863年到1963年的过程中，浅色个体减少，中间色个体增加，深色个体也减少．自然选择的对象：a．直接对象是生物的变异性状（表现型）；间接对象是相关的基因型；根本对象是与变异性状相对应的基因，即自然选择的实质是环境对变异所对应的基因的选择，因而可以改变种群的基因频率．自然选择的因素：对生物的变异起选择作用的是个体所处的自然环境．自然选择的动力：生存斗争．

A、在实验数据中不能得到深体色和浅体色个体的性别比例；故A错误．
B、由图可知，1863到1963年蝴蝶深、浅体色个体逐渐被淘汰，中间体色个体适应环境，不容易被天敌发现，存活下来；故B正确．
C、进化的基本单位是种群，自然选择使得种群中浅色个体容易生存，相应种群基因频率增加；故C错误．
D、深体色和浅体色类群能相互交配的，进行基因交流，不存在生殖隔离；故D错误．
故选B．

点评：
本题考点： 生物进化与生物多样性的形成；物种的概念与形成．

考点点评： 本题考查自然选择的作用的相关知识，意在考查学生理论联系实际，综合运用所学知识解决自然界和社会生活中的一些生物学问题．

Potato chips were a call George grum chefs in 1863 invention

B