[单项选择]A female-male mosaic fruit fly may be formed, if there is chromosome loss or ______.
A. equal division during sperm generation
B. abnormal mitosis during merogenesis (fertilized egg cleavage)
C. meiosis in embryo
D. meiosis when sperm is tailed

[单项选择]A female-male mosaic fruit fly may be formed, if there is chromosome loss or______．
A. equal division during sperm generation
B. abnormal mitosis during merogenesis(fertilized egg cleavage)
C. meiosis in embryo
D. meiosis when sperm is tailed

[简答题]In a fruit fly (Drosophila melanogaster)family, alleles aer, brt and cts are all homozygous in recessive somatic cells. The 3 loci of aer. brt and cts are linked in order. Crossing the female flies of this family with male wild-type fruit flies, and make F₁ heterozygous individuals intercross, the F₂ are produced as follows:
+ + + 4365
aer brt cts 1168
aer brt + 278
+ + cts 269
aer + + 150
+ brt cts 141
aer + cts 16
+ brt + 13
(1)Please analyse and calculate the recombination frequency between aer and brt and that between brt and cts.
(2)How much is the coefficient of interference

[单项选择]In a strain of fruit fly, after several times of artificial hybridizations, the map distances of the given loci is A-B=10 m.u., A-C=20 m.u., A-D=25 m.u., B-C=30 m.u., B-D=15 m.u., If the genetic map is drawn according to these humbers, the correct locus order should be ______.
A. DCBA
B. DBAC
C. CADB
D. ACDB

[填空题]In Island 3 Lagrange stations people could "fly" through their centers where there was no gravity.

[简答题]fruit

[填空题]The sale fell during April but rose again in May to reach the same level as in March.

[填空题]Low-income shoppers may gain ______ on fruit and vegetable products.

[单项选择]I have only one ticket. ______ you ______ he may take it.
A. Both ... and
B. Neither ... nor
C. Either ... or

[单项选择]What’s the date today
[A] May 4th. [B] May 5th. [C] May 6th.

[单项选择]What fruit does New Zealand export mostWhat fruit does New Zealand export most
A. Kiwi fruit
B. pear
C. apple

[填空题]When firms need to raise capital they may choose to sell or float securities. These new issues of securities typically are marketed to the public by investment bankers in the primary market. Trading of already-issued securities among investors (26) in the secondary market.
There are two types of primary market issues of common stock. (27) public offerings, or IPOs, are stocks issued by a formerly (28) owned company that is going public, that is, selling stock to the public for the first time. Seasoned new issues are offered by companies that already have floated (29) . For example, a sale by IBM of new shares of stock would (30) a seasoned new issue.
In the case of bonds, we also (31) two types of primary market issues, a public offering and a private (32) . The former refers to an issue of bonds sold to the general investing public that can then be traded on the secondary market. The (33)