Which of the following best explains why carbon dioxide must be added to water? a. Carbon dioxide bubbles can’t be produced if it is not added to the solution.

b. Carbon dioxide maintains the green color seen in the plant.

c. Carbon dioxide is a needed reactant (input) of photosynthesis.

d. Carbon dioxide does not need to be added.

By using internet

The answer is atmosphere. there are four spheres of the earth: 1. geosphere (from greek word 'geo' = ground), 2. hydrosphere (from greek word 'hydro' = water), 3. biosphere (from greek word 'bio' = life), and 4. atmosphere (from greek word 'atmo' = air). a magnetosphere is a region of space around astronomical objects controlled by the magnetic field of that object. through the process of elimination, since lightning is present in the air, it can be found in the atmosphere.