焦虑 发表于 2025-3-28 17:35:54
Ecosystem Engineers, Keystone Species,anus. A curious feature of the Nematodes is that the tissues of which their bodies are composed are made up of very few large cells; there are no cilia anywhere, no blood system, and no breathing organs. The eggs are covered by a hard shell. The young Nematode hatches looking very much like an adult束缚 发表于 2025-3-28 22:24:01
Patrick M. A. James,Marie-Josée Fortin(.) on their bodies which are arranged in groups on each segment; they are used to obtain a hold on the sides of burrows, and they are a very valuable means of identifying a specimen. Worms all have distinct heads and tails though it is sometimes difficult to see which is which, but the mouth is oveSuppository 发表于 2025-3-29 02:53:17
Heinrich Walter,Siegmar-W. Brecklee the limbs used for locomotion (i.e. walking or swimming). The skin on the surface of the animals contains a particular substance called chitin and is waterproof. Frequently most of the skin tends to be rather hard and brittle, and movement would be difficult were it not that between the segments o急性 发表于 2025-3-29 06:28:07
Heinrich Walter,Siegmar-W. Breckleciliated, and the cilia make currents which collect the small organisms used as food, and transport them to the mouth. Polyzoa possess a proper gut, which terminates in an anus; ovaries and testes (they are hermaphrodites); and a rudimentary nervous system. The fresh-water polyzoa reproduce asexuallpanorama 发表于 2025-3-29 09:45:01
http://reply.papertrans.cn/16/1577/157605/157605_45.pngBET 发表于 2025-3-29 12:48:58
http://reply.papertrans.cn/16/1577/157605/157605_46.pngfigment 发表于 2025-3-29 16:20:21
http://reply.papertrans.cn/16/1577/157605/157605_47.pngacolyte 发表于 2025-3-29 21:09:04
http://reply.papertrans.cn/16/1577/157605/157605_48.png漂亮才会豪华 发表于 2025-3-30 00:44:48
The True Worms (,),(.) on their bodies which are arranged in groups on each segment; they are used to obtain a hold on the sides of burrows, and they are a very valuable means of identifying a specimen. Worms all have distinct heads and tails though it is sometimes difficult to see which is which, but the mouth is ove外面 发表于 2025-3-30 06:29:31
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