Science

For engineering, you need to go for JEE Mains to get admission in IITs and NITs and other top colleges. For medical, you need to go for NEET to get admission in top college in India. So you can choose your best.

You must take PCB that is physics, biology and chemistry.

It depends what percentage you have in your 4 major subjects.

Yes, you will have to do this.

It depends on the percentage you get in your 3rd year or you can get admission through entrance exams.

You can take admission in research Institutes like TIFR, IISER, IISc, etc. For that, you will have to take their entrance test. These institutes are pioneer institutes of research in India.

Biotechnology course is available in Delhi University. Here, you can apply or in may private colleges like VIT, Vellore.

1. Amity Institute of Food Technology, Noida
2. Anna University, Chennai
3. C V Raman College of Engineering, Bhubaneswar, Orissa
4. Desh Bhagat Engineering College, Punjab
5 Doon Valley Institute of Engineering and Technology, Karnal, Haryana
6. Gondwana University
MIDC Road Complex
Gadchiroli, Maharashtra
7. Guru Gobind Singh Indraprastha University GGSIPU Delhi
8. Guru Nanak Institute Of Technology - GNIT, Kolkata, West Bengal.
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Keep asking and keep smiling.

Yes, it is very much required.