Journal of Natural and Agricultural Sciences, Volume 6, Number 19, December-2019, is a quarterly Journal edited by ECORFAN-Bolivia. Santa Lucia N-21, Barrio Libertadores, Cd. Sucre. Chuquisaca, Bolivia, http://www.ecorfan.org/bolivia/rj_ciencias_naturales.php, revista@ecorfan.org. Editor in Chief: Ramos Escamilla-María, Co-editor: Serrudo González-Javier. ISSN: 2410-356X. Responsible for the last update of this issue ECORFAN Computer Unit. Imelda Escamilla Bouchán, PhD. Vladimir Luna Soto, PhD. Updated as of December 31, 2019. The opinions expressed by the authors do not necessarily reflect the views of the publisher of the publication. It is strictly forbidden the total or partial reproduction of the contents and images of the publication without permission of the National Institute of Copyright.