didermic embryo

例句：

1. 1. The sponge has a porous structure that allows it to absorb water.
   海绵的结构是多孔的，可以吸收水分。
2. 2. The perforate shell of the clam protects its soft inner tissue.
   蛤蜊的穿孔壳保护着它的柔软内组织。
3. 3. The porous nature of the coral makes it an ideal habitat for marine life.
   珊瑚的多孔性质使其成为海洋生物的理想栖息地。