Article: But although it meets the definition of outer space, the atmospheric density within the first few hundred kilometers above the Karman line is still sufficient to produce significant drag on satellites. Most artificial satellites operate in this region called low Earth orbit and must fire their engines every few days to maintain orbit.[citation needed] The drag here is low enough that it could theoretically be overcome by radiation pressure on solar sails, a proposed propulsion system for interplanetary travel.[citation needed] Planets are too massive for their trajectories to be significantly affected by these forces, although their atmospheres are eroded by the solar winds.

Question: What system could possibly be used for interplanetary travel?
Ans: solar sails

Article: Other stories result from a natural rivalry between two or more characters. Outside of performance, these are referred to as feuds. A feud can exist between any number of participants and can last for a few days up to multiple decades. The feud between Ric Flair and Ricky Steamboat lasted from the late 1970s into the early 1990s and allegedly spanned over two thousand matches (although most of those matches were mere dark matches). The career-spanning history between characters Mike Awesome and Masato Tanaka is another example of a long-running feud, as is the case of Stone Cold Steve Austin vs. Mr. McMahon, one of the most lucrative feuds in the World Wrestling Federation (WWF) during 1998 and 1999.

Question: What are rivalries often called?
Ans: feuds

Article: Purebred dogs of one breed are genetically distinguishable from purebred dogs of other breeds, but the means by which kennel clubs classify dogs is unsystematic. Systematic analyses of the dog genome has revealed only four major types of dogs that can be said to be statistically distinct. These include the "old world dogs" (e.g., Malamute and Shar Pei), "Mastiff"-type (e.g., English Mastiff), "herding"-type (e.g., Border Collie), and "all others" (also called "modern"- or "hunting"-type).

Question: the Border collie is an example of what type of dog?
Ans: herding

Article: Despite its relative lexical unity, the two dialectal blocks of Catalan (Eastern and Western) show some differences in word choices. Any lexical divergence within any of the two groups can be explained as an archaism. Also, usually Central Catalan acts as an innovative element.

Question: As what can divergence in the groups be shown?
Ans:
as an archaism