There are several online quizzes and tests available for the Zoology optional subject, which can be helpful for UPSC and other competitive exams. These quizzes and tests can be found on various online platforms, including EduRev. Here is a detailed explanation of the available options:

1. EduRev:
- EduRev is an online learning platform that offers a wide range of educational resources, including quizzes, tests, and study materials for various subjects, including Zoology.
- To access the Zoology quizzes and tests on EduRev, you can visit their website and search for the specific subject.
- The quizzes and tests on EduRev are designed to cover the entire syllabus of Zoology optional subject, ensuring comprehensive preparation.

2. Topic-wise Quizzes:
- Many online platforms, including EduRev, offer topic-wise quizzes for Zoology.
- These quizzes focus on specific topics within Zoology, allowing you to assess your understanding and knowledge of individual concepts.
- By attempting these topic-wise quizzes, you can identify your strengths and weaknesses in different areas of Zoology and plan your preparation accordingly.

3. Full-length Mock Tests:
- Mock tests are available on various platforms, including EduRev, that simulate the actual exam environment.
- These mock tests cover the entire syllabus of the Zoology optional subject and provide an opportunity to practice answering questions within the given time limit.
- Mock tests also help in familiarizing yourself with the exam pattern and improve time management skills.

4. Previous Years' Question Papers:
- Another useful resource for practice is the previous years' question papers.
- Many online platforms, including EduRev, provide access to previous years' question papers for the Zoology optional subject.
- By solving these question papers, you can get an idea about the type of questions asked in the exam and the level of difficulty.

5. Discussion Forums and Community:
- Online platforms often have discussion forums and communities where you can interact with fellow aspirants studying Zoology optional subject.
- Participating in these forums allows you to discuss doubts, share study materials, and gain insights from others' perspectives.

In conclusion, there are various online quizzes and tests available for the Zoology optional subject, including those on EduRev. These resources offer topic-wise quizzes, full-length mock tests, previous years' question papers, and provide a platform for discussion and interaction with other aspirants. Utilizing these resources can be beneficial for comprehensive preparation and improving your chances of success in the UPSC and other competitive exams.