About _% of photosynthesis is carried out by terrestrial plants, while the rest occurs in oceans, lakes, and ponds.

Explanation

The correct answer is 10%. Terrestrial plants, such as trees, grasses, and other land-based vegetation, contribute to about 10% of the total photosynthesis on Earth. This process involves capturing sunlight and converting it into chemical energy. However, the majority of photosynthesis occurs in aquatic environments, primarily by phytoplankton in oceans, lakes, and ponds, which account for the remaining 90%. The other options (20%, 30%, and 40%) are incorrect, as they overestimate the contribution of terrestrial plants.