Question

The large increase in atmospheric carbon dioxide in the last 50 years most likely comes from

• A. An increase in cellular respiration
• B. Increased decomposition by bacteria
• C. An increase in the burning of fossil fuels
• D. An increase in photosynthesis

Answer 1

The correct option is C An increase in the burning of fossil fuels

Cellular Respiration (a) and Decomposition (b) both add to carbon dioxide, but there is no evidence that these have increased over the last 50 years. Photosynthesis (d) decrease carbon dioxide. However, an increase in the burning of fossil fuels (C) has increased. For example, there are many more vehicles burning gasoline than in the past, coal is used in household and industries, diesel is used for in working of certain construction equipments etc

moreover, urbanisation and industrialization has lead to deforestation, leading to decrease in number of trees that fix carbon dioxide.

So, the correct answer is 'An increase in the burning of fossil fuels'