Respuesta :
The study of an environment is called ecology.
The correct answer is D.
The thing which can be used again is called recycle things. A few examples are as follows:-
- Plastic
- Electronic items.
According to the question, all of them is recyclable because the water is used again in a different form, the carbon dioxide is used up by the plants and release oxygen and it is used by humans and release carbon dioxide and become a cycle.
The used water is going into the ocean which will evaporate and fill into the cloud. Later on, that cloud is brust and rain falls down to the nearest water source.
Hence, The correct answer is D.
For more information, refer to the link:-
https://brainly.com/question/13899929
