Hello Aspirant,

See you can appear for 10+2 but there is no need to appear for all subjects again because through Open board either of your state or from NIOS you can appear for only PCM subjects without wasting your year because for CUSAT you only need 50% or more marks in 10+2 in PCM combination and in other subjects you should have passed at least so you can appear for PCM subjects through any of the central/state recognized board of education. And if you are able to secure more then 50% marks in PCM combination subjects then you can use these marks to satisfy the eligibility criteria for CUSAT.

For more details kindly check out the link given below :-

CUSAT Kochi Admission: Eligibility, Dates, Application, Fees (careers360.com)

I hope this information helps you.

Good Luck!!