Q: The Ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains high concentrations of ozone (O) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth's atmosphere as a whole is about 0.3 parts per million. The ozone layer is mainly found in the lower portion of the stratosphere, from approximately 20 to 30 kilometers (12 to 19 mi) above Earth, although its thickness varies seasonally and geographically.

Where is the ozone layer located in earth's atmosphere?
A: the lower portion of the stratosphere , from approximately 20 to 30 kilometers ( 12 to 19 mi ) above Earth. How to explain the answer? The relevant sentence in the passage is: The ozone layer is mainly found in the lower portion of the stratosphere, from approximately 20 to 30 kilometers (12 to 19 mi) above Earth, although its thickness varies seasonally and geographically.

Q: Desalination is a process that extracts mineral components from saline water. More generally, desalination refers to the removal of salts and minerals from a target substance, as in soil desalination, which is an issue for agriculture.

Answer this question based on the passage: which term is defined as the removal of salts and minerals from seawater?
A: Desalination. How to explain the answer? This is the relevant information: Desalination is a process that extracts mineral components from saline water.

Q: "How Long Will I Love You?" is a song by folk-rock band The Waterboys from their fifth studio album, Room to Roam (1990). Written by Mike Scott, it was released as the album's lead single. The song was subsequently covered by English singer Ellie Goulding and released as the second single from her album Halcyon Days (2013). Goulding's version is included on the soundtrack to the 2013 film About Time, which also features a different cover by Jon Boden, Sam Sweeney and Ben Coleman.

Answer this question: who sang the original how long will i love you?
A: The Waterboys. How to explain the answer? This is the relevant information: "How Long Will I Love You?" is a song by folk-rock band The Waterboys from their fifth studio album, Room to Roam (1990).

Q: Super Smash Bros. was introduced in 1999 for the Nintendo 64. It was released worldwide after selling over a million copies in Japan. It featured eight characters from the start (Mario, Donkey Kong, Link, Samus, Yoshi, Kirby, Fox, and Pikachu), with four unlockable characters (Luigi, Captain Falcon, Ness, and Jigglypuff), all of them created by Nintendo or one of its second-party developers.

Based on this passage, how many unlockable characters in super smash bros?
A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
four. How to explain the answer? To answer this question, we should know that: It featured eight characters from the start (Mario, Donkey Kong, Link, Samus, Yoshi, Kirby, Fox, and Pikachu), with four unlockable characters (Luigi, Captain Falcon, Ness, and Jigglypuff), all of them created by Nintendo or one of its second-party developers.