问题 填空题

李华有耳垂,母亲也有耳垂,但李华的两个姐妹无耳垂,请回答下列问题。

(1)耳垂特征在遗传学上称为________。

(2)李华母亲有耳垂,他也有耳垂,这是一种________现象;李华母亲有耳垂,他的两个姐妹无耳垂,这是一种________现象。

(3)李华体细胞的染色体数是46条,那么他母亲通过配子给他______条染色体。

答案

(1)性状

(2)遗传、变异

(3)23

完形填空
完形填空。
     Canada is the second largest country is the world. It is over 7,000 kilometres from the __1__ coast
to the east. It __2__  six time zones. __3__   it is 9 a. m. in Vancouver on the west coast,it is 1:30 p, m.
in St John's on the east coast.
     English and French __4___  the two main languages in Canada. About 60 percent of __5  _ people
speak English, and about 25 percent speak French. More  __6_   70 percent of its population live in
cities near the US border (边缘).
     Ottawa is the capital. Every year millions of tourists go there to __7__  museums and take part in the
cultural activities. Toronto is the largest city of the country __8__  about 2. 5 million people. Montreal is
__9_   second biggest French-speaking city in the world.
     The maple leaf (枫叶) is the national symbol of Canada. The Canadian flag has a red maple leaf on a
red __10_ white background (背景).
( )1. A. west    
( )2. A. is      
( )3. A. Which    
( )4. A. are      
( )5. A. their    
( )6. A. up      
( )7. A. see      
( )8. A. with    
( )9. A. a        
( )10. A. or     
B. east  
B. had    
B. What  
B. is    
B. his    
B. over  
B. visit  
B. for    
B. an    
B. and    
C. south    
C. has      
C. Where    
C. will be  
C. its      
C. about    
C. look    
C. from    
C. the      
C. but      
D. north    
D. have    
D. When    
D. has been
D. our      
D. than    
D. find    
D. at      
D. 不填      
D. however  
单项选择题