Breathing is rhythmic. It is the intake of oxygen and expulsion of carbon dioxide. Respiration is the production of energy in the body, which includes breathing, mastication etc. Through this process, oxygen is inhaled. This inhaled oxygen is used to burn/oxidize/break down the food (glucose). This reaction produces energy which is used to carry out various activities going in our body. Our body needs continuous supply of energy to carry out these activities. So, respiration is a continuous process which makes us able to meet energy demands of our body. If respiration comes to halt the person will die..

The correct answer is option 'B' - Respiration. Respiration is a biological process that occurs continuously in our body to provide oxygen to the cells and remove carbon dioxide as a waste product. It is an essential process for the survival of all living organisms, including humans.

Respiration can be divided into two main types:

1. External Respiration:
External respiration is the process of exchanging gases between the atmosphere and the body. It involves the following steps:

- Breathing: Breathing is the process of inhaling oxygen-rich air and exhaling carbon dioxide-rich air. It is controlled by the respiratory center in the brain. During inhalation, the diaphragm contracts, and the chest cavity expands, allowing air to enter the lungs. During exhalation, the diaphragm relaxes, and the chest cavity contracts, pushing out the carbon dioxide-rich air.

- Gas Exchange: In the lungs, oxygen from the inhaled air diffuses into the bloodstream through the thin walls of the alveoli (tiny air sacs). At the same time, carbon dioxide from the bloodstream diffuses into the alveoli to be exhaled.

2. Internal Respiration:
Internal respiration is the process of exchanging gases between the bloodstream and the body's cells. It involves the following steps:

- Oxygen Transport: Oxygen binds to hemoglobin molecules in red blood cells and is transported to cells throughout the body. This oxygen is used by the cells to produce energy through a process called cellular respiration.

- Carbon Dioxide Transport: Carbon dioxide, a waste product of cellular respiration, is released by the cells into the bloodstream. It is transported back to the lungs, where it is exhaled during the external respiration process.

Respiration is a continuous process that ensures the supply of oxygen to the cells and the removal of carbon dioxide, which is a waste product. Without respiration, cells would not receive the necessary oxygen for energy production, and the accumulation of carbon dioxide would be toxic to the body.

In conclusion, respiration is a vital biological process that occurs continuously in our body to provide oxygen to the cells and remove carbon dioxide. It involves both external and internal respiration processes, which ensure the exchange of gases between the atmosphere, bloodstream, and cells.