Yes, you are eligible to appear for the CLAT exam despite Biology being listed as an additional subject, as the exam does not mandate specific subject requirements. The eligibility criteria for CLAT (UG) are as follows:

1. Educational Qualification : You must have passed Class 12th (or equivalent) from a recognized board.
2. Minimum Marks : General/OBC/PwD/NRI/PIO/OCI candidates need at least 45% aggregate marks, while SC/ST candidates require 40%.
3. Subject Combination : There are no restrictions on the stream or subjects studied in Class 12th. Whether you had Science, Commerce, or Humanities, you are eligible as long as you meet the minimum percentage and passing criteria.

Since your overall Class 12th status is marked as “Passed,” and Biology is not a required subject for CLAT, your RT in Biology will not affect your eligibility. Additionally, CLAT does not differentiate between main and additional subjects when assessing eligibility.

However, ensure that your Class 12th mark sheet and passing certificate are valid and recognized by your board. If you have any doubts, you may contact the CLAT Consortium for confirmation. Focus on preparing for the exam, as your stream or subject choice in Class 12th does not play any role in the test. The key is meeting the overall percentage requirement and passing status, which you have achieved.