题目

Thanksgiving Day is a public holiday.It is on the fourth Thursday in November in the USA and on the second Monday in October in Canada. For many Americans it is the most important holiday apart from(除……之外)Christmas.Schools，offices and most businesses close for Thanksgiving Day，and many people make the whole weekend a vacation. Today people celebrate Thanksgiving Day to remember the early days.The most important part of the celebration is a traditional dinner with foods that come from North America.The meal includes(包括)turkey，sweets，potatoes and so on. On Thanksgivi下列有关人类基因的描述中，错误的是A．基因是遗传物质中决定生物性状的小单位B．一对基因中，可能都是隐性的C．基因都是成对存在的D．一对基因，一个来自父方，一个来自母方