A simple reaction happening in plants is a major contributor for the sustenance of animal life on earth. This reaction, which is termed as photosynthesis, releases oxygen to the atmosphere as a byproduct. The reaction happens within the green parts of the plants and uses the energy from the sun to power it. Complex carbohydrates are created from simple substances like water and carbon dioxide.

Every day, large volumes of carbon dioxide are released into the atmosphere through various processes. Automobiles are the main sources of this gas. What we breathe out is also carbon dioxide. The green plants help fix the carbon dioxide of the atmosphere and convert that into oxygen.

The actual site of photosynthesis reaction is the chloroplast. They are green plastids which are present everywhere in the plants but mainly on the green leaves. The density of chloroplast on a leaf is about half a million per square millimeter! All members of the plant kingdom have the ability to perform this reaction. Photosynthesis happens even in the water plants using the carbon dioxide present in the water. In fact about 90% of the oxygen released is contributed by the water plants.

Photosynthesis is probably the only reaction through which so much of energy enters the ecosystem. Using just light energy from sun, water and carbon dioxide, each year billions of kilograms of energy is produced. More than 150 billion metric tons of sugar is produced annually! If there were no plants on our earth, we would have all starved for want of food. Also, photosynthesis is the only means by which carbon dioxide is fixed and oxygen released to the atmosphere. If not for the plants and this photonic reaction, by now the carbon dioxide content in the atmosphere would have been so high that it would not have supported any animal life.