I got 75% in 12th midterm and 83% in 11th final exams. Is this score good enough to pursue mechanical engineering in USA?

Yes.you can 

You can join BTech course at Institute of Chemical Technology, Mumbai if you have passed your Class 12 exams with Science streams. Candidates need to score a minimum of 45% aggregate marks to meet the basic application norms. For reserved category students, the university relaxes this minimum requir

It depends on the stream and college. For DU's Science colleges, CUET UG scores decide admission rather than 12th marks directly. For engineering, JEE Main or JEE Advanced ranks are needed along with meeting a minimum Class 12 percentage cutoff. Medical admission always needs a valid NEET UG score,

Yes, students can apply for a BDes course while waiting for their class 12th results. They can appear for entrance exams like CUET or UCEED. Enrollment will happen on provisional basis, which means it is on the condition that they pass class 12th with the college desired percentage and all required

Yes, students can apply for BSc Agriculture while waiting for their class 12th results. They can appear for entrance exams like CUET or ICAR. Enrollment will happen on provisional basis, which means it is on the condition that they pass class 12th with the college desired percentage and all required