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horseshoe crab

(Encyclopedia)horseshoe crab, large, primitive marine arthropod of the family Limulidae, related to the spider and scorpion and sometimes called a king crab (a name also used for the largest of the edible true crab...

moth

(Encyclopedia)moth, any of the large and varied group of insects which, along with the butterflies, make up the order Lepidoptera. The moths comprise the great majority of the 100,000 species of the order, and abou...

mercury poisoning

(Encyclopedia)mercury poisoning, tissue damage resulting from exposure to more than trace amounts of the element mercury or its compounds. Elemental mercury (the silver liquid familiar from thermometers) is the mos...

lithium

(Encyclopedia)lithium lĭthˈēəm [key] [Gr.,=stone], metallic chemical element; symbol Li; at. no. 3; interval in which at. wt. ranges 6.938–6.997; m.p. about 180.54℃; b.p. about 1,342℃; sp. gr. .534 at 20�...

leaf

(Encyclopedia)CE5 Microscopic cross section of the leaf blade CE5 Types of leaves leaf, chief food-manufacturing organ of a plant, a lateral outgrowth of the growing point of stem. The typical leaf consist...

Krebs cycle

(Encyclopedia)Krebs cycle, series of chemical reactions carried out in the living cell; in most higher animals, including humans, it is essential for the oxidative metabolism of glucose and other simple sugars. The...

pendulum

(Encyclopedia)pendulum, a mass, called a bob, suspended from a fixed point so that it can swing in an arc determined by its momentum and the force of gravity. The length of a pendulum is the distance from the point...

bow and arrow

(Encyclopedia)bow and arrow, weapon consisting of two parts; the bow is made of a strip of flexible material, such as wood, with a cord linking the two ends of the strip to form a tension from which is propelled th...

zinc

(Encyclopedia)zinc, metallic chemical element; symbol Zn; at. no. 30; at. wt. 65.38; m.p. 419.58℃; b.p. 907℃; sp. gr. 7.133 at 25℃; valence +2. Zinc is a lustrous bluish-white metal. It is found in Group 12 o...

Stoicism

(Encyclopedia)Stoicism stōˈĭsĭzəm [key], school of philosophy founded by Zeno of Citium (in Cyprus) c.300 b.c. The first Stoics were so called because they met in the Stoa Poecile [Gr.,=painted porch], at Athe...