Each segment has the same sets of organs and, in most polychaetes, has a pair of parapodia that many species use for locomotion. Septa separate the segments of many species, but are poorly defined or absent in others, and Echiura and Sipuncula show no obvious signs of segmentation.ach segment has the same sets of organs and, in most polychaetes, has a pair of parapodia that many species use for locomotion. Septa separate the segments of many species, but are poorly defined or absent in others, and Echiura and Sipuncula show no obvious signs of segmentation.
Chicxulub is most famous for being near the geographic center of the Chicxulub crater, an impact crater discovered by geologists on the YucatÃ¡n Peninsula and extending into the ocean. It was created by the impact some 65 million years ago of the Chicxulub impactor, an asteroid or comet which caused the CretaceousâPaleogene extinction event, which led to the demise of the dinosaurs.
[el kas'tiÊo]), Spanish for the castle), also known as the Temple of Kukulcan, is a Mesoamerican step-pyramid that dominates the center of the Chichen Itza archaeological site in the Mexican state of Yucatan. YucatÃ¡n the building is more formally designated by archaeologists As Chichen Itza STRUCTURE. 5b18rom Wikipedia, the free encyclopedia. El Castillo (. [el kas'tiÊo]), Spanish for the castle), also known as the Temple of Kukulcan, is a Mesoamerican step-pyramid that dominates the center of the Chichen Itza archaeological site in the Mexican state of Yucatan. yucatÃ¡n