<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31344869</termId><termName>oxygen</termName><termType>PT</termType><termNote><![CDATA[ Nonmetallic chemical element (O). It is a colorless, odorless, tasteless gas, the most plentiful element in the Earth's crust; its most important compound is water. ]]></termNote><termCreatedDate>2026-03-30 20:33:01</termCreatedDate><relation><relationType>UF</relationType><termId>31344870</termId><termName>O</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31320550</termId><termName>oxygen, oxygen isotopes, allotropes, compounds</termName><termType>PT</termType></relation><relation><relationType>RT</relationType><termId>31343606</termId><termName>oxygen isotopes</termName><termType>PT</termType></relation></term>  </Zthes>