Is it necessary to install Google XML Sitemaps plugin?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  Dinesh Kumar: We submit sitemap to google webmastertools by completing Add Site section.
  It is necessary to install Google XML Sitemaps plugin ? I have submitted to webmastertools by above method. ;
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  Mark Hall: no, its fine
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  Dinesh Kumar: Very thank you Mark.. :)
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  Edwin Jonk: From the expert panel in this weeks SEO Questions hangout on air on 00:04:35 into the YouTube video: https://dumbseoquestions.com/q/is_it_necessary_to_install_google_xml_sitemaps_plugin +Dinesh Kumar
  
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  Dinesh Kumar: thank you Edwin :) .  ;video is clearing many questions. ;