Article: In addition to re-writing the classification of annelids and 3 previously independent phyla, the molecular phylogenetics analyses undermine the emphasis that decades of previous writings placed on the importance of segmentation in the classification of invertebrates. Polychaetes, which these analyses found to be the parent group, have completely segmented bodies, while polychaetes' echiurans and sipunculan offshoots are not segmented and pogonophores are segmented only in the rear parts of their bodies. It now seems that segmentation can appear and disappear much more easily in the course of evolution than was previously thought. The 2007 study also noted that the ladder-like nervous system, which is associated with segmentation, is less universal previously thought in both annelids and arthropods.[n 2]

Question: What offshoots of polychaetes are only segmented in the rear?
Ans: pogonophores


Article: Guam lies between 13.2°N and 13.7°N and between 144.6°E and 145.0°E, and has an area of 212 square miles (549 km2), making it the 32nd largest island of the United States. It is the southernmost and largest island in the Mariana island chain and is also the largest island in Micronesia. This island chain was created by the colliding Pacific and Philippine Sea tectonic plates. Guam is the closest land mass to the Mariana Trench, a deep subduction zone, that lies beside the island chain to the east. Challenger Deep, the deepest surveyed point in the Oceans, is southwest of Guam at 35,797 feet (10,911 meters) deep. The highest point in Guam is Mount Lamlam at an elevation of 1,334 feet (407 meters).

Question: How deep is the Mariana Trench located near Guam?
Ans: 35,797


Article: When Ibn Sina was 22 years old, he lost his father. The Samanid dynasty came to its end in December 1004. Ibn Sina seems to have declined the offers of Mahmud of Ghazni, and proceeded westwards to Urgench in modern Turkmenistan, where the vizier, regarded as a friend of scholars, gave him a small monthly stipend. The pay was small, however, so Ibn Sina wandered from place to place through the districts of Nishapur and Merv to the borders of Khorasan, seeking an opening for his talents. Qabus, the generous ruler of Tabaristan, himself a poet and a scholar, with whom Ibn Sina had expected to find asylum, was on about that date (1012) starved to death by his troops who had revolted. Ibn Sina himself was at this time stricken by a severe illness. Finally, at Gorgan, near the Caspian Sea, Ibn Sina met with a friend, who bought a dwelling near his own house in which Ibn Sina lectured on logic and astronomy. Several of Ibn Sina's treatises were written for this patron; and the commencement of his Canon of Medicine also dates from his stay in Hyrcania.

Question: At what age did Avicenna lose his father?
Ans: 22


Article: In 2007 Torsten Struck and colleagues compared 3 genes in 81 taxa, of which 9 were outgroups, in other words not considered closely related to annelids but included to give an indication of where the organisms under study are placed on the larger tree of life. For a cross-check the study used an analysis of 11 genes (including the original 3) in 10 taxa. This analysis agreed that clitellates, pogonophorans and echiurans were on various branches of the polychaete family tree. It also concluded that the classification of polychaetes into Scolecida, Canalipalpata and Aciculata was useless, as the members of these alleged groups were scattered all over the family tree derived from comparing the 81 taxa. In addition, it also placed sipunculans, generally regarded at the time as a separate phylum, on another branch of the polychaete tree, and concluded that leeches were a sub-group of oligochaetes rather than their sister-group among the clitellates. Rouse accepted the analyses based on molecular phylogenetics, and their main conclusions are now the scientific consensus, although the details of the annelid family tree remain uncertain.

Question: What did Rouse decide leeches were a subgroup of?
Ans:
oligochaetes