Which Atmosphere term is correctly associated with location: “gradually merges into outer space”, and also with “particles are extremely sparse”?

Correct Answer: Option B — Exosphere. Exosphere is correct because it is gradually merges into outer space. Exosphere is also associated with particles are extremely sparse. A further identifying fact is that Exosphere is particles are extremely sparse. Another useful fact is that Exosphere is associated with light gases such as hydrogen and helium dominate. Why the other options are incorrect: Option A — Ozone layer: It is located mainly in the stratosphere and is associated with absorbs much of the Sun's harmful ultraviolet radiation; those are the identifying facts of Ozone layer. Option C — Jet stream: It is generally found near the tropopause and is associated with mainly flows from west to east; those are the identifying facts of Jet stream. Option D — Trade winds: It is blow from subtropical highs toward the equatorial low and is associated with deflected westward by the Coriolis effect; those are the identifying facts of Trade winds. Exam Takeaway: Link Exosphere with “gradually merges into outer space” and “particles are extremely sparse” for quick revision.