most abundant
61Abundance of the chemical elements — Estimated proportions of matter, dark matter and dark energy in the universe. Only the fraction of the mass and energy in the universe labeled atoms is composed of chemical elements. The abundance of a chemical element measures how relatively… …
62CHON — Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur CHON (or CHNOPS) is an mnemonic acronym for the four most common (or six most essential) elements in living organisms: carbon, hydrogen, oxygen, and nitrogen. Thes …
63Virus — This article is about the biological agent. For other uses, see Virus (disambiguation). For a generally accessible and less technical introduction to the topic, see Introduction to viruses. Viruses …
64calcium — /kal see euhm/, n. Chem., Biol. a silver white divalent metal, occurring combined in limestone, chalk, gypsum, etc., occurring also in vertebrates and other animals, as a component of bone, skeletal mass, shell, etc., and as a necessary element… …
65chondrichthian — /kon drik thee euhn/, n. any member of the class Chondrichthyes, comprising the cartilaginous fishes. [ < NL, equiv. to chondr CHONDR + Gk ichthýes (pl.) fish] * * * ▪ fish class Introduction class name Chondrichthyes, or Selachii any… …
66coleopteran — /koh lee op teuhr euhn, kol ee /, adj. 1. belonging or pertaining to the order Coleoptera. n. 2. a beetle. [1840 50; COLEOPTER(A) + AN] * * * ▪ insect Introduction any member of the insect order Coleoptera, consisting of the beetles and weevils …
67fern — fernless, adj. fernlike, adj. /ferrn/, n. any seedless, nonflowering vascular plant of the class Filicinae, of tropical to temperate regions, characterized by true roots produced from a rhizome, triangular fronds that uncoil upward and have a… …
68Fern — /ferrn/, n. a female given name. * * * Any of about 10,000–12,000 species (division Filicophyta) of nonflowering vascular plants that have true roots, stems, and complex leaves and reproduce by spores. Though ferns were once classified with the… …
69gastropod — /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.… …
70nebula — 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 …
