inward-facing surface
61tunnels and underground excavations — ▪ engineering Introduction Great tunnels of the world Great tunnels of the worldhorizontal underground passageway produced by excavation or occasionally by nature s action in dissolving a soluble rock, such as limestone. A vertical opening …
62gastropod — /gas treuh pod /, n. 1. any mollusk of the class Gastropoda, comprising the snails, whelks, slugs, etc. adj. 2. Also, gastropodous /ga strop euh deuhs/. belonging or pertaining to the gastropods. [1820 30; < NL Gast(e)ropoda a class of mollusks.… …
63respiration, human — ▪ physiology Introduction the process by which oxygen is taken up and carbon dioxide discharged. The design of the respiratory system The human gas exchanging organ, the lung, is located in the thorax, where its delicate tissues are… …
64locomotion — /loh keuh moh sheuhn/, n. the act or power of moving from place to place. [1640 50; see LOCOMOTIVE, MOTION] * * * Any of various animal movements that result in progression from one place to another. Locomotion is classified as either… …
65echinoderm — /i kuy neuh derrm , ek euh neuh /, n. any marine animal of the invertebrate phylum Echinodermata, having a radiating arrangement of parts and a body wall stiffened by calcareous pieces that may protrude as spines and including the starfishes, sea …
66Bicycle brake systems — are used to slow down, or brake a bicycle. There have been various types through history, and several are still in use today.HistoryEarly bicycles such as the high wheeled penny farthing bikes were fitted with spoon brakes. As they were fixed… …
67dinosaur — /duy neuh sawr /, n. 1. any chiefly terrestrial, herbivorous or carnivorous reptile of the extinct orders Saurischia and Ornithischia, from the Mesozoic Era, certain species of which are the largest known land animals. 2. something that is… …
68Collapse of the World Trade Center — Coordinates: 40°42′41.12″N 74°00′44.00″W / …
69Crookes tube — A Crookes tube. The electrons travel in straight lines from the cathode on the left, shown by the shadow cast by the cross on the fluorescence on the righthand wall. The anode is at the bottom. A Crookes tube is an early experimental electrical… …
70biblical literature — Introduction four bodies of written works: the Old Testament writings according to the Hebrew canon; intertestamental works, including the Old Testament Apocrypha; the New Testament writings; and the New Testament Apocrypha. The Old… …
