Biology

Hi Ishita,
The eligibility criteria for this course clearly says that one needs marks of Biology/Biotech, Chemistry, Mathematics & Physics to calculate the aggregate. All 4 of them.
I will suggest you to visit the following link to know more about the eligibility criteria.
http://www.sxccal.edu/admissions/SXCAdmission2018/UG8102/EligibilityCriteria.htm
All the best.

Chemistry and mental agility are compulsory. Rest, you have a choice between Maths and Physics /Biology /Agriculture. That means, yes you can attempt agriculture with chemistry and mental agility.

Sorry to say, but B.tech in food technology requires physics, chemistry and maths subject from 10+2.
Infact, B.Sc in food tech also asks 50% or 55% aggregate in 10+2 with subjects physics, chemistry, maths and biology/home science.
There maybe some colleges offering diploma/graduate degree under B.Sc in food tech without maths.

Best Courses After 12th for Science Students with PCM, PCB and PCMB are mentioned at the link provided below:
https://www.shiksha.com/courses-after-12th/science.

You just need to clear class 12 examination. If you have interest in commerce field and planning to do MBA in future, BA will be a good decision. Yes, you can do B.A after 12th in biology. So, BA course is open for students from every stream.

Most of the institutes do not offer pure specialisation in Genetic engineering at the under graduate level. It is generally offered as a subsidiary I. e. along with other subjects like microbiology, biochemistry etc. In universities like Osmania University, Kakatiya University. Specialisation in genetic engineering is generally offered at the post graduate level. Some of the institutes offering the same include IIT Delhi and Kharagpur, JNU, BITS Pilani. B.Sc. In Genetics is offered by Institute of Genetic Engineering in Kolkata. There is no entrance exam as admission is based on 12th marks.

You can complete your B.Sc in biology or you can join B.Sc. Nursing so that in future you may get chance in doctor field. You don't lose your confidence. You may get a chance to go in the doctor field.