Engineering

Probably yes, it is compulsory, but there will be many students who would be from non-biology background, but still they do. If you are good at learning, then you will learn it. So, don't worry about it.

B.Tech is much better option from the job point of view or higher studies perspective. Most of the companies prefer B.Tech holder students. And also, if you have plans for higher studies, many foreign and Indian university admit B.Tech graduates.

First of all, check the requirements for the course for which you are applying. Then take the test like GRE TOEFL or SAT. Apply before the deadline and pay the application fee.

BITSAT is the most favourable entrance exam after JEEs.

Rankings in JEE exams are decide on the basis of your secured marks. Percentage criteria is 75% which is common to all. More weightage is given to JEE marks.