Question

A fish thrives better in an aquarium if green plants are growing in it This is because

• A. They can eat plants for their survival
• B. They like green surroundings
• C. They get more oxygen
• D. They inhale CO2 released by plants

Answer 1

The correct option is C They get more oxygen

The fishes produce CO${}_2$ by the activity of respiration. This CO${}_2$ produced is taken up the aquatic plants for the process of photosynthesis to occur and in turn, they give out O${}_2$ which can be used by fishes for respiratory processes again. Thus a fish thrives better in an aquarium if green plants are growing in it as a green plant acts as a purifier of water by removing the CO${}_2$ and adding the O${}_2$ to the immediate surrounding.

So, the correct answer is 'They get more oxygen'.