作者rbhank30 (X)
看板Biology
标题[问题] campbel0e testbank Ch32 26题请高手解惑
时间Mon Mar 3 15:20:16 2014
【问题】：第26题的本文如下:
Trichoplax adhaerens(Tp) is the only living species in the phylum Placozoa.
Idividials are about 1 mm wide and only 27 um high, are irregularly shaped,
and consist of a total of about 2000 cells, which are diploid(2n=12). There
are 4 types of cells, none of which are nerve or muscle cells, and none of
which have cell walls. They move using cilia, and any "edge" can lead.
Tp feeds on marine microbes, mostly unicellular green algae, by crawling
atop the algae and trapping it between its ventral surface and the substrate.
Tp sperm cells have never been observed, nor have embryos past the 64-cell
(blastula)stage.
26. On the basis of information in the paragraph above, which of these should
be able to be observed in Tp?
<A> the act of fertilization
<B> the process of gastrulation
<C> eggs
<D> all three of the listed responses are correct.
【个人看法】：因为没有精子,因此A选项先删除, 而又没有blastula stage 因此觉得
B选项也不太可能。剩下C，也就是答案给的正确选项，但是不知道原因为何，依题
目中的描述，我认为该生物应该行无性繁殖，且没有少於64细胞的胚时期，有可能是行
出芽,断裂,或分裂, 因此为何答案会是egg不解?麻烦请各位高手大大帮忙解惑,感激不尽
【参考资料/连结】：
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※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 114.45.52.154
1F：推 qiet:既然有所谓的embryo, 不是就代表有egg(卵)? 03/03 20:51
2F：→ qiet:还有那句话应该是指说胚时期过不了64个细胞的stage 03/03 20:52
3F：→ qiet:所以会有个受精卵曾经被观察到可以发遇到64-cell stage 03/03 20:52
4F：→ rbhank30:感谢解答! 很棒的解释,我了解了~! 03/04 15:37