Osmoregulation is the process by which an organism regulates the water balance in its body and maintains the homeostasis of the body.

The liver, kidneys, brain, autonomic nervous system, and the endocrine system help to maintain homeostasis.

Cell is the smallest structural and functional unit of living organisms and it is capable of forming specific funtion

Metabolism is the sum total of the biochemical reactions involves in release and utilization of energy or energy exchange within the organisms.

► Air enters in Inspiration
► Air comes out Expiration

► Alveoli are the workhouses of respiratory system.
► The exchange of oxygen and carbondioxide takes place in alveoli.
► It takes up oxygen and gives out carbondioxide.

There are 4 types of tissues.
i) Epithelial tissue
ii) Muscular tissue
iii) Connective tissue
iv) Nervous tissue

► Th foetus consists of multitude of cells of different shape, size and content.
► Foetal cells gradually attain change in structure and function.
► This process is known as cell differentiation.

In a closed room there will be poor ventilation. The oxygen in the closed room or crowded area will be used up by the people. As a respiration the concentration of carbon di oxide in air increases. There will no supply of oxygen. As oxygen is necessary for respiration we feel suffocated in closed and crowded places.

a) Why did the doctor advised him to go to the playground?
► Playing games in the playground regulates the breathing rate. It increases the capacity of lungs to hold more oxygen. Playground games may serve as a solution to minor respiratory problems in kids. It inhibits shallow breathing. So the doctor advised him to go to the playground.
b) What is the use of pranayamam?
► Pranayama ensures more oxygen to lungs and good for hearts too. In pranayama, the retention of breathe helps supply of oxygen and carbondioxide thus facilitates better work of lungs and helps brain to work more efficiently. Pranayama enhances autonomic nervous system which controls heart rate, glandular secretions, respiration, digestion and blood pressure.