Class 9 Biology Test Test Time Explore various categories of non-fiction books. The Fundamental Unit of Life Learn about the structure and functions of cells, including important organelles like the nucleus, mitochondria, and vacuoles. Tissues Understand the differences between plant and animal tissues and their various types like muscular, connective, and epithelial tissue. Diversity in Living Organisms Explore the classification of organisms from Monera to Animalia and learn about evolutionary relationships among living beings. Why Do We Fall Ill? Learn the causes of diseases, the difference between infectious and non-infectious diseases, and how to maintain good health. Natural Resources Study air, water, soil, and the biosphere along with the pollution and conservation of these valuable natural resources. Improvement in Food Resources Understand various practices used in agriculture and animal husbandry to improve food production and sustainability.