Acknowledgements

My gratitude goes to the Department of Biological Sciences at North-West University, Mafikeng Campus for financial support while carrying out the study. I extend my gratitude to Professor C.N. Ateba, Professor N.P. Sithebe, and Dr. K. Sichilongo for all their support and guidance. I would like to thank the Ministry of Basic Education of Botswana for providing me time to carry out the research and financial support in one way or the other.
