利用扦插、嫁接等方法繁殖花卉或果树的最主要的优点是（ ）
A．缩短植物的成熟时间
B．增强植物生活力
C．保留了亲代的优良性状
D．有利于大量繁殖新个体
答案：C
题目分析：嫁接、扦插没有经过雌雄两性生殖细胞的而结合，遗传物质没有发生变异，能保证遗传物质的稳定遗传．保留了亲代的优良性状．嫁接既能保持接穗品种的优良性状，又能利用砧木的有利特性，达到早结果、增强抗寒性、抗旱性、抗病虫害的能力，还能经济利用繁殖材料、增加苗木数量．常用于果树、林木、花卉的繁殖上；也用于瓜类蔬菜育苗上．嫁接分枝接和芽接两大类，前者以春秋两季进行为宜，尤以春季成活率较高，后者以夏季进行为宜．
This March is a busy month in Shanghai. There's a lot to do. Here are the highlights. Live Music - Late Night Jazz Enjoy real American jazz from Herbie Davis, the famous trumpet(小号) player. He's coming with his new 7-piece band, Herbie' s Heroes. Herbie is known to play well into the early hours, so don't expect to get much sleep. This is Herbie' s third visit to Shanghai. The first two were sold out, so get your tickets quickly.
Take your partners and get ready to dance till you drop. Scottish dancing is fun and easy to learn. Instructors(教练) will show the dances. The live band, Gordon Stroppie and the Weefrees, are also excellent.
There are 120,000 pieces on show here. You can see the whole of Chinese history. It' s always interesting to visit, but doubly(双重) so at the moment with the Egyptian Tombs exhibition. There are lots of mummies(木乃伊) and more gold than you've ever seen before. Let us know if you see a mummy move!
Sushi is getting really big in Shanghai. In Japan, it' s become an art form. The most famous Sushi 'artist' is Yuki Kamura. She' s also one of the few female chefs in Japan. She' ll be at Sushi Scene all of this month.
小题1:If you are going to attend an activity at 8: 00p. m. on Saturday, which one can you choose?
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