Student A:By volume, dry air contains 78.09 % nitrogen, 20.95 % oxygen, 0.93 % argon, 0.04 % carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1 % at sea level, and 0.4 % over the entire atmosphere. Air content and atmospheric pressure vary at different layers, and air suitable for use in photosynthesis by terrestrial plants and breathing of terrestrial animals is found only in Earth's troposphere and in artificial atmospheres.

Answer this question based on the passage: what is the percentage of o2 in air?
Student B:OK... To answer the above question, the relevant sentence is: By volume, dry air contains 78.09 % nitrogen, 20.95 % oxygen, 0.93 % argon, 0.04 % carbon dioxide, and small amounts of other gases.
20.95 %.

Student A:The Milky Way is a barred spiral galaxy with a diameter between 150,000 and 200,000 light-years (ly). It is estimated to contain 100 -- 400 billion stars. There are probably at least 100 billion planets in the Milky Way. The Solar System is located within the disk, 26,490 ( 100) light-years from the Galactic Center, on the inner edge of the Orion Arm, one of the spiral-shaped concentrations of gas and dust. The stars in the innermost 10,000 light-years form a bulge and one or more bars that radiate from the bulge. The galactic center is an intense radio source known as Sagittarius A *, likely a supermassive black hole of 4.100 ( 0.034) million solar masses.

Where is our solar system in the milkyway?
Student B:OK... The relevant sentence in the passage is: The Solar System is located within the disk, 26,490 ( 100) light-years from the Galactic Center, on the inner edge of the Orion Arm, one of the spiral-shaped concentrations of gas and dust.
within the disk , 26,490 ( 100 ) light - years from the Galactic Center , on the inner edge of the Orion Arm.

Student A:Context: The field of view is the extent of the observable world that is seen at any given moment. In the case of optical instruments or sensors it is a solid angle through which a detector is sensitive to electromagnetic radiation.

Question: what does the term field of view mean?
Student B:OK... To answer the question, consider the following: The field of view is the extent of the observable world that is seen at any given moment.
the extent of the observable world that is seen at any given moment.

Student A:Passage: "Always on My Mind" is a song by Johnny Christopher, Mark James, and Wayne Carson, recorded first by Gwen McCrae (as "You Were Always on My Mind") and Brenda Lee in 1972. The song has been a crossover hit, charting in both the country and western and pop categories.

Question: Based on this passage, who sang the song you were always on my mind?
Student B:
OK... This is the relevant information: "Always on My Mind" is a song by Johnny Christopher, Mark James, and Wayne Carson, recorded first by Gwen McCrae (as "You Were Always on My Mind") and Brenda Lee in 1972.
Johnny Christopher , Mark James , and Wayne Carson , recorded first by Gwen McCrae ( as '' You Were Always on My Mind '' ) and Brenda Lee in 1972.