DENDROLOGY

Detailed explanation-1: -Tropical rainforests are often called the “lungs of the planet” because they generally draw in carbon dioxide and breathe out oxygen. But the amount of carbon dioxide they absorb, or produce, varies hugely with year-to-year variations in the climate.

Detailed explanation-2: -The majority of this production is from oceanic plankton-drifting plants, algae, and some bacteria that can photosynthesize. One particular species, Prochlorococcus, is the smallest photosynthetic organism on Earth. But this little bacteria produces up to 20% of the oxygen in our entire biosphere.

Detailed explanation-3: -Once covering 14% of land on Earth, rainforests now make up only 6%. Since 1947, the total area of tropical rainforests has probably been reduced by more than half, to about 6.2 to 7.8 million square kilometers (3 million square miles).