| Among the 11 extant orders of arachnids, Araneae and Acari are by far the most species rich. |
| In Treatise on the quadrilateral al-Tusi gave the first extant exposition of the whole system of plane and spherical trigonometry. |
| His responsiveness to nature recalls one of Atwood's beliefs about qualities extant in much Canadian literature. |
| And finally, in the last extant part of the apocryphal Gospel of Mary, Mary is defended by the disciple Levi, presumably the son of Alphaeus. |
| The impala and rhebok were also not included in tribe-level analyses because each is the sole extant member of its tribe. |
| The authors have divided the woods into five groups according to their relationship to extant plants. |
