The air is primarily composed of nitrogen (about 78%) and oxygen (about 21%). The remaining 1% consists of various trace gases such as argon, carbon dioxide, neon, helium, and more.
Reading Standards for Literacy in Science and Technical Subjects
Craft and Structure
Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context relevant to grades 6-8 texts and topics.