Changes

[1] [http://www.deardoctor.com/dentistry/blog/tag/toothbrush-lifespan deardoctor.com/dentistry/blog/tag/toothbrush-lifespan]

<br>[2] [https://www.google.com/search?source=hp&ei=0RPEXJiMM4u8gwfx-oww&q=what+is+the+average+lifespan+of+a+human&btnK=Google+Search&oq=what+is+the+average+lifespan+of+a+human&gs_l=psy-ab.3..0i70i251j0l9.1075.7543..7758...3.0..0.130.2103.40j2......0....1..gws-wiz.....0..0i131j0i22i30j0i22i10i30.lxrTR0cnEFk Google search engine answer]