Although an infant's color vision is not as sensitive as an adult's, it is generally believed that babies have good color vision by five months of age. Most babies start crawling at about 8 months old, which helps further develop eye-hand-foot-body coordination.
A language tree, or family tree with languages substituted for real family members, has the form of a node-link diagram of a logical tree structure. Such a diagram contains branch points, or nodes, from which the daughter languages descend by different links.
Old English treo, treow tree (also wood), from Proto-Germanic *trewan (cf. Old Frisian tre, Old Saxon trio, Old Norse tre, Gothic triu), from PIE *deru-oak (cf. Sanskrit dru tree, wood, daru wood, log; Greek drys oak, doru spear; Old Church Slavonic drievo tree, wood; Serbian drvo tree, drva wood; Russian drevo tree, wood; Czech drva; Polish drwa wood; Lithuanian derva pine wood; Old Irish daur, Welsh derwen oak, Albanian drusk oak).