Tissues: Plant and Animal Tissues
A tissue is a group of cells having a common origin, similar structure and function and held together by a cementing substance. Example: Connective tissue.
Biology Class 9
Cells: The Unit of Life
Cells vary in number (singlecelled: Amoeba; few-celled: Spirogyra, multi-celled: Man), size (smallest:
Bacteria, longest: Nerve cell, largest: Ostrich egg) and shape (columnar: Epithelial cells).
The Respiratory System
Respiration is the catabolic process of releasing energy from simple sugar, glucose, for carrying out
various life processes.
Digestive System
Digestion is the process of breakdown of naturally occurring foodstuffs into a diffusible form. It is a process which makes the foods soluble and of such a chemical nature that they can be absorbed through living membranes.
Five Kingdom Classification
One of the earliest systems of classification, called the Two Kingdom Classification, was proposed by Carolus Linnaeus in 1758.
Introducing Biology
The study of living things, namely plants, animals and human beings, is called Biology. Human Biology is the study of man as a living organisms