CBSE 12th

You can choose a stream of your liking. Eligibility: Candidates must have a 10 + 2 or Intermediate in any discipline. Students must be fluent in English with strong communication skills and must have aptitude for design. You will need a minimum of 50% in your class 12th to qualify for successful application to this course.
Students in their final year of graduation can also apply. Regards.

B.Sc (Nursing)-Admission Procedure:
B.Sc Nursing admission is purely based on entrance exams held in between April-June. Candidates can fill the application form in both online and offline mode. For filling online, candidates need to go to the administrator website of the concerned entrance exam and fill the requirements. B.Sc. (Nursing): Eligibility Criteria:
Candidates who wish to pursue B.Sc. Nursing course are required to fulfill the below mentioned eligibility criteria. B.Sc. (Basic) - Candidates should pass 10+2 in Physics, Chemistry and Biology and he/she should be medically fit. Regards.

Please refer to the link provided below for details on IISER Entrance Exam 2018 Eligibility. You can check for your eligibility to appear for the IISER Entrance Exam from the criteria mentioned at the link provided below:
https://www.shiksha.com/science/exams/iiser-entrance-exam.

Yes, you may change your additional subject in class 12th. I also changed my additional subject from Maths to Biology in class12th. But, it is necessary that you may apply for it before filling the form of class 12th.

The basic eligibility of a B.Sc course in interior designing is a pass in 10+2 and the approximate tuition fee varies from 3 Lacs INR to 15 lac INR. Regards.

NATA is the only entrance examination for CEPT (B.Arch). You shall also appear with your higher secondary school marks.

Company Secretary Course is conducted in three different levels. Foundation Level, Intermediate Level and Final level. For being eligible for Foundation level, you should have passed 10+2 (or equivalent) from a recognized board. Once you qualify the Foundation Level you can apply for Intermediate Level and
After qualifying Intermediate Level, you can apply for Final Level. If you have completed Graduation then you are not required to qualify Foundation Level. You can directly apply for Intermediate Level. The Duration of foundation and intermediate course is 8 months and 9 months respectively. Regards.

Yes, you can apply for Japanese course. You need to have 50% marks in English at 10+2 level (45% marks for OBC category).

Please check for your eligibility to apply for a course in BTC from the criteria mentioned below:
BTC (Basic Training Certificate): Eligibility
Among the diverse eligibility criteria, the most important one to get admission in any of the Basic Teacher Training colleges in the nation is the successful completion of higher secondary or 10+2 level of examination. It is preferable to score at least 50 % marks in the 10 + 2 level of study. Regards.