Чем дальше друг от друга гены расположены в хромосоме, тем выше вероятность перекреста между ними и тем больше процент гамет с перекомбинированными генами, а следовательно, и больше особей в потомстве, отличных от родителей. Это происходит потому, что близко расположенные гены имеют больше вероятности оказаться вместе, так как они редко разделяются при перекресте. Перекрест служит важным источником генетической изменчивости, потому что при нем образуются две хромосомы, содержащие в себе гены обеих исходных хромосом.
ex. 1
fill in the gaps with (a) few or (a) little.
1. a: what did you do during your flight?
b: i read few magazines and i slept for an hour.
2. a: is there any cake left?
b: there's very little left.
3. a: do you speak spanish?
b: no, i know very few words in spanish.
4. a: when are you coming back?
b: soon. i'm only going away for few days.
5. a: i think this soup needs more flavour.
b: ok. i will add little more salt.
6. a: we must hurry.
b: that's true. we have very little time.
7. a: poor him! he looks lonely.
b: he's ver shy and has very few friends.
ex. 2
complete the text with a lot of, much or many.
courchevel is one france's most famous ski destinations. 1. a lot of rich and famous people spend their holidays there every year. in fact, there aren't 2. many ski resorts as nice as courchevel! it has 3. a lot of great restaurants, beatiful hotels and expensive shops. but don't worry if you don; t have 4. much money. there are 5. many cheap places to stay and eat for people who are on a budget. and the skiing is fantastic. ti's perfect for both beginner and expert skiers, because there sre 6. a lot of ski paths to choose from. everyone loves courchevel.
why not come and see why!
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