1. Ecological balance is a state of dynamic equilibrium within a community of organisms in a habitat or ecosystem.
2. It can happen when the diversity of the living organisms remains relatively stable.
3. Gradual changes do take place but that happens only through natural succession.
4. It can also be explained as a stable balance in the numbers of each species in an ecosystem.
5. This occurs through competition and cooperation between different organisms where population remains stable.
6. This balance is brought about by the fact that certain species compete with one another determined by the environment in which they grow.
7. This balance is also attained by the fact that some species depend on others for their food and sustenance.
8. Such accounts are encountered in vast grasslands where the herbivorous animals (deer, zebras, buffaloes, etc.) are found in plenty.

Input devices

An input device can send data to another device, but it cannot receive data from another device. Examples of input devices include the following.

• Keyboard and Mouse - Accepts input from a user and sends that data (input) to the computer. They cannot accept or reproduce information (output) from the computer.
• Microphone - Receives sound generated by an input source, and sends that sound to a computer.
• Webcam - Receives images generated by whatever it is pointed at (input) and sends those images to a computer.

Output devices

An output device can receive data from another device and generate output with that data, but it cannot send data to another device. Examples of output devices include the following.

• Monitor - Receives data from a computer (output) and displays that information as text and images for users to view. It cannot accept data from a user and send that data to another device.
• Projector - Receives data from a computer (output) and displays, or projects, that information as text and images onto a surface, like a wall or screen. It cannot accept data from a user and send that data to another device.

The vital capacity is the total volume of air that can be expired after a maximum inhalation or maximum air that a person can breathe in after forced expiration. It is an important measure of a person's respiratory health.

The poem The Laburnum Top is a beautiful poem in which the poet has used the Laburnum Tree and goldfinches as a symbol of life and its fluctuations. In this poem, the poet describes how the visit of a goldfinch changes the Laburnum tree. The goldfinch transforms the tree and makes it come alive as the chicks of the goldfinch start to rustle and chirp on seeing her. Once the goldfinch leaves the tree, it becomes quiet and still again. The Laburnum tree symbolises the pattern of our life in general, which is usually dull and inanimate. The goldfinch breaks the usual pattern and makes it lively. Without the goldfinch, the Laburnum tree is just like another tree. In other words, it is the attitude of a person towards life that makes life meaningful and worth living.

Central problems of an economy are. What to produce, How to produce, and For whom to produce. 'What to produce' relates to the problem of choice of goods and services to be produced. 'How to produce' relates to the choice of technique of production. It involves a choice between labour-intensive technique and capital - intensive technique. 'For whom to produce' relates to the distribution of goods and services across different sections of the society. It focuses on the issue of Economic Equality.

​It aims to develop students' physical competence and knowledge of movement and safety, and their ability to use these to perform in a wide range of activities associated with the development of an active and healthy lifestyle.

Physical education is a course taught in school that focuses on developing physical fitness and the ability to perform and enjoy day-to-day physical activities with ease.Kids, as well as adults, benefit from regular exercise. Health benefits from regular exercise include: stronger muscles and bones, increased coordination and energy, and decreased risk of developing chronic diseases such as type 2 diabetes. For most kids, exercise means being physically active during play, recess, and physical education class, also known as P.E. Physical education contributes to each child’s total growth and development. Kids also develop skills necessary to participate in a wide range of activities, such as soccer, basketball, or swimming. Regular physical education classes prepare kids to be physically and mentally active, fit, and healthy into adulthood. An effective physical education program should include engaging lessons, trained P.E. teachers, adequate instructional periods, and student evaluation.

The CT scan was led by Dr. Hawaas. The scan came up with new clues about his life and death. It provided precise data for an accurate forensic reconstruction of King Tut. Tut’s body was examined over a computer screen with the help of the CT scan. It showed a grey head, neck vertebrae, a hand, several images of rib cages and a transaction of the skull.