Science

Yes, you are eligible for this. You can fill the application form by visiting the site Of JNU. For more information regarding the admission process, visit JNU website.

Yes, you are eligible for M.Sc. Many universities offer this course. One of the finest universities of India, Delhi University, also offers this course. Admission for this course is based on the entrance exam. IIT also offers the post graduation programme M.Sc Maths. So be prepared for the entrance

No, these are very less marks for admission to B.Sc B.Ed.

Yes, you definitely can apply for JAM exam for Masters in Science. Your score is very good in the 4th semester.

I think no, because your percentage is below from first division.

Hey,
It is one of the finest colleges of Delhi university. Faculty members of B.sc (H) Chemistry are very experienced and have a very effective learning. You get a great exposure in this college.
You can take admission in this college.

Eligibility for M.Tech-
A minimum CPI of 6.0 or 55% of marks in the qualifying degree/Diploma as indicated below:
Note: All regular category candidates (except those having B.Tech/BDes degrees from an IIT with a minimum CPI of 7.0).

Both the courses has different direction and different scope on future. You can't compare engineering with a B.Sc courses. Both the courses has its own merits.
Gender never decides the courses. It is your interest in which side you can do better. Choose that side.
I suggest you to go with Engineerin