outer radiation zone
61tree — treelike, adj. /tree/, n., v., treed, treeing. n. 1. a plant having a permanently woody main stem or trunk, ordinarily growing to a considerable height, and usually developing branches at some distance from the ground. 2. any of various shrubs,… …
62Tree — /tree/, n. Sir Herbert Beerbohm /bear bohm/, (Herbert Beerbohm), 1853 1917, English actor and theater manager; brother of Max Beerbohm. * * * I Woody perennial plant. Most trees have a single self supporting trunk containing woody tissues, and in …
63endocrine system, human — ▪ anatomy Introduction group of ductless glands (gland) that regulate body processes by secreting chemical substances called hormones (hormone). Hormones act on nearby tissues or are carried in the bloodstream to act on specific target organs… …
64optics — /op tiks/, n. (used with a sing. v.) the branch of physical science that deals with the properties and phenomena of both visible and invisible light and with vision. [1605 15; < ML optica < Gk optiká, n. use of neut. pl. of OPTIKÓS; see OPTIC,… …
65chemical element — Introduction also called element, any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed. This article considers the… …
66environment — environmental, adj. environmentally, adv. /en vuy reuhn meuhnt, vuy euhrn /, n. 1. the aggregate of surrounding things, conditions, or influences; surroundings; milieu. 2. Ecol. the air, water, minerals, organisms, and all other external factors… …
67nebula — nebular, adj. /neb yeuh leuh/, n., pl. nebulae / lee , luy /, nebulas. 1. Astron. a. Also called diffuse nebula. a cloud of interstellar gas and dust. Cf. dark nebula, emission nebula, reflection nebula …
68plant — plantable, adj. plantless, adj. plantlike, adj. /plant, plahnt/, n. 1. any member of the kingdom Plantae, comprising multicellular organisms that typically produce their own food from inorganic matter by the process of photosynthesis and that… …
69Asteroid belt — For the album by Velvet Chain, see Asteroid Belt (album). The asteroid belt (shown in white) is located between the orbits of Mars and Jupiter. The asteroid belt is the region of the Solar System located roughly between the orbits of the planets… …
70dating — I In geology and archaeology, the process of determining an object s or event s place within a chronological scheme. Scientists may use either relative dating, in which items are sequenced on the basis of stratigraphic clues (see stratigraphy) or …
