有关遗传变异的下列四种说法，请你判断（）
①基因型为Dd的豌豆在进行减数分裂时，会产生雌雄两种配子，其数量比接近1∶1
②基因自由组合定律的实质是：F1产生配子时，等位基因分离，非等位基因自由组合
③将基因型为Aabb的玉米花粉授到基因型为aaBb的玉米植株上，所结籽粒胚的基因型是：AaBb、Aabb、aaBb、aabb
④染色体中DNA的脱氧核苷酸序列、种类、数量，三者中有一个发生改变，就会引起染色体变异
A.四种都对
B.四种都不对
C.只有一种对
D.只有一种不对
参考答案：C
请根据所提供的单据，判断所填制“出境货物报检单”各项内容的正误，完成判断题(见报检单上标注的题号)。
SAlES CONTRACT
No.：QJ760125
Date：Oct.10，2008
The Buyer: MoonRiver Import & Export corporation, Busan, Korea
The Seller: Jiangsu Hongling Industrial&Trade Corporation
This contract is made by and between the Seller and the Buyer, whereby the Seller agrees to sell and the Buyer agrees to buy the under-mentioned goods according to the terms and conditions stipulated below:
(1)
| Name of commodity | Quantity | Unit Price | Total Price |
| TV SET52CM (Dragon Brand) | 1000SETS 1000CTNS | USD 80/SET | USD 80000 |
(2)Packing: In Carton
(3)Port of Loading: LIANYUNGANG PORT, Jiangsu, China
(4)Port of destination: BUSAN PORT, Korea
(5)Shipping Mark: N/M
(6)Date of Shipment: Apr.2008 / By Vessel
(7)Terms of Payment: Letter of Credit (No.WE570346 )
(8)Documents Required: Certificate of Quality, issued by CIQ indicating the No.of L/C
The Buyer The Seller
______ ______
