There are several mock tests available for the diagram-based questions in Botany Optional. These mock tests can be a valuable resource for students preparing for the Botany Optional section of the UPSC exam. These tests provide an opportunity for students to practice their diagram-drawing skills and familiarize themselves with the types of questions that may be asked in the exam. Here are some details about the mock tests available:

1. EduRev:
EduRev is a popular online platform that offers a wide range of study materials and resources for various competitive exams, including UPSC. They provide mock tests specifically designed for the Botany Optional section. These tests cover a diverse range of topics and include diagram-based questions to help students assess their understanding and preparation level.

2. Test series by coaching institutes:
Many coaching institutes that offer Botany Optional coaching also provide mock tests as part of their test series. These test series are designed to simulate the actual UPSC exam environment and help students evaluate their performance. The mock tests usually include diagram-based questions, allowing students to practice drawing accurate and well-labeled diagrams.

3. Previous year question papers:
One of the most effective ways to prepare for the diagram-based questions in Botany Optional is to solve previous year question papers. These papers provide an insight into the types of questions that have been asked in the past and help students familiarize themselves with the exam pattern. By solving these papers, students can also practice drawing diagrams and understand the level of detail required in their answers.

4. Online forums and communities:
There are several online forums and communities where UPSC aspirants gather to discuss their preparation strategies and share resources. These platforms often have dedicated sections for Botany Optional, where students can find and share mock tests for diagram-based questions. By actively participating in these communities, students can not only access mock tests but also learn from the experiences and insights of their peers.

5. Self-preparation:
In addition to the aforementioned resources, students can also create their own mock tests for diagram-based questions. They can compile a list of important topics from the Botany Optional syllabus, draw diagrams related to those topics, and test themselves by labeling and explaining the different parts. This self-preparation approach allows students to focus on their weak areas and customize the mock tests according to their specific needs.

Overall, there are several options available for students preparing for the diagram-based questions in Botany Optional. By regularly practicing these mock tests, students can improve their diagram-drawing skills and enhance their overall performance in the UPSC exam.