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简述毛蟹的幼体发育特点。

答案

参考答案:

幼体孵出后,即离开母体行浮游生活。由于刚孵出时的幼体体形与水蚤相似,故称为溞状幼体。随蜕皮次数的增加,胸肢也随之增加,腹部狭长,通常分6节,末端为1尾部叉,从第二期溞状幼体开始腹部变为7节,并出现腹肢。蟹类的溞状幼体有2~5期不等,以5期最为常见。最后一期溞状幼体蜕皮之后,即变为大眼幼体。大眼幼体通常为一期,经蜕皮后变为第一期幼蟹。

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We already live in an ever-communicated world that will only become mere so in the next tech era. We’ve (1) that gets us so much information. We’ve got every second (2) , we’ve get computers and laptops, we’ve get personal organizers and we’re just being (3) and every advance in technology seems to create more and more communications at us. We are sort of (4) .
Research suggests that all the multi-tasking may actually make our brains (5) , producing a world-wide increase in IQ (6) and mere in recent decades. Is there any real benefit in (7) we new have to go through
We’re net becoming a race of (8) , but many de think certain skills are enhanced and certain are net. You knew the ability to (9) , to answer a dozen e- mails in five minutes, or to fill out (10) . That’s enhanced. But when someone is out there with his kids (11) or something like that, he’s got his cell phone in his pocket. He’s always wondering, "Gee, did I get a voicemail " This might have negative effects (12) .
Creativity is something that happens slowly. It happens when your brain is just (13) , just playing, when it (14) which you hadn’t thought of, or maybe you have time to read a book. You are a businessperson but you have time to (15) ,or about a philosopher and something that happened long age or something or some idea (16) . Actually, it might occur to you that you (17) in that way, and so it’s this mixture of unrelated ideas that feeds your productivity, (18) . And if your mind is disciplined to answer every e-mail, then you don’t have time for that playful noodling. You don’t have time for (19) . So I think maybe we’re getting smarter in .some senses, but ever-communication is (20) and to our reflection.

We already live in an ever-communicated world that will only become mere so in the next tech era. We’ve (1) that gets us so much information. We’ve got every second (2) , we’ve get computers and laptops, we’ve get personal organizers and we’re just being (3) and every advance in technology seems to create more and more communications at us. We are sort of (4) .
Research suggests that all the multi-tasking may actually make our brains (5) , producing a world-wide increase in IQ (6) and mere in recent decades. Is there any real benefit in (7) we new have to go through
We’re net becoming a race of (8) , but many de think certain skills are enhanced and certain are net. You knew the ability to (9) , to answer a dozen e- mails in five minutes, or to fill out (10) . That’s enhanced. But when someone is out there with his kids (11) or something like that, he’s got his cell phone in his pocket. He’s always wondering, "Gee, did I get a voicemail " This might have negative effects (12) .
Creativity is something that happens slowly. It happens when your brain is just (13) , just playing, when it (14) which you hadn’t thought of, or maybe you have time to read a book. You are a businessperson but you have time to (15) ,or about a philosopher and something that happened long age or something or some idea (16) . Actually, it might occur to you that you (17) in that way, and so it’s this mixture of unrelated ideas that feeds your productivity, (18) . And if your mind is disciplined to answer every e-mail, then you don’t have time for that playful noodling. You don’t have time for (19) . So I think maybe we’re getting smarter in .some senses, but ever-communication is (20) and to our reflection.