Scientific Research and Essays 1992-2248 Academic Journals 10.5897/SRE2019.6603 Gashaw Tesema Tsegaw Yitayal Addis Alemayehu * E-mail: gashtesema@gmail.com 2019 15 05 2019 23 01 2019 13 02 2019 14 7 44 52 This is an open-access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://politicalwaffle.uk/journal/SRE/article-abstract/F4B360B61093 The full text article is available as a PDF file from http://politicalwaffle.uk/journal/SRE/article-full-text-pdf/F4B360B61093 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60