The digestive system helps in breaking food down to usable nutrients and energy carrying molecules while disposing of waste. Respiratory system obtains oxygen for combustion of food and discharges carbon dioxide. Renal system disposes other dissolved waste products of cell activity.

Circulatory system moves blood along with other essential nutrients to or from cells where they are needed or produced. The coordination of all these systems is carried out by the brain and nervous system. The electrical and chemical signals carried by nerves and hormones provide communication between all the other organ systems and thereby synchronize their functions.

Thus, biology is study of life which is endlessly challenging and uplifting. Biology need not demand relevance towards nature, as it is a natural science. Our very aliveness emphasizes the intimacy of the connection between the discipline of biology and our everyday concerns.

The knowledge of biology that has been gained, provides us with a tool of extraordinary power to improve the human condition and lessen human impact on the world. Biology is the foundation for medical research which improved quality of life with new medical therapies.

Let us explore this exciting study of 'Life' to know more about ourselves and the world around us.