This process is functional in removing carbon dioxide from the atmosphere

The correct option is photosynthesis.

To understand why photosynthesis is functional in removing carbon dioxide from the atmosphere, let us look at the details of the process:

1. What is Photosynthesis?
Photosynthesis is a biological process used by plants, algae, and certain bacteria to synthesize nutrients from carbon dioxide and water using sunlight as an energy source. The general chemical equation representing this process is:
$$6{\mathrm{CO}}_2+6H_{2}O+\text{light energy}\Rightarrow C_6{H}_{12}{O}_6+6O_2$$

2. How it removes Carbon Dioxide:
During this process, autotrophic organisms absorb carbon dioxide (${\mathrm{CO}}_2$) directly from the atmosphere through tiny pores in their leaves called stomata. The carbon from ${\mathrm{CO}}_2$ is fixed into organic compounds like glucose ($C_6{H}_{12}{O}_6$), which the plant uses for growth and energy. Oxygen ($O_2$) is released back into the atmosphere as a byproduct.

3. Why other options are incorrect:
- Lightning: Primarily aids in nitrogen fixation by converting atmospheric nitrogen into forms plants can use, but does not remove carbon dioxide.
- Deforestation: The clearing of forests reduces the number of trees available to perform photosynthesis, leading to an increase (rather than removal) of atmospheric carbon dioxide.
- Burning of fossil fuels: Combusts carbon-based materials, which releases large amounts of carbon dioxide into the atmosphere.