Question

In a sealed tank is a large sprig of elodea and a snail. The tank is kept for several weeks on a sunny windowsill. Both the plant and snail live and appear to be healthy. Why does this happen?

Option 1: The snail produces oxygen, and the plant produces carbon dioxide.
Option 2: Both the snail and the plant produce oxygen.
Option 3: The snail produces carbon dioxide, while the plant produces oxygen.
Option 4: Both the snail and plant produce carbon dioxide.

Answer 1

In a sealed ecosystem on a sunny windowsill, a snail and a sprig of elodea can survive because the snail produces carbon dioxide that the plant uses for photosynthesis, leading to the production of oxygen, which the snail then uses for respiration. Therefore, the most appropriate correct option is 1.

Step-by-step explanation:

The scenario described involves a closed ecosystem with a snail and a sprig of elodea (a water plant). The reason both the snail and the plant can survive in this environment is due to their complementary biological processes. The snail, being an animal, breathes in oxygen and exhales carbon dioxide as a waste product. On the other hand, the elodea plant uses this carbon dioxide during the process of photosynthesis, which results in the production of oxygen and glucose. Glucose is used by the plant for growth and other metabolic processes, while the oxygen produced is released into the environment and can be used by the snail for respiration. This cycling of gases helps maintain a balance within the sealed tank, allowing both the snail and the plant to thrive, especially in the presence of sunlight that drives the plant's photosynthesis.