Class 12-science

70% for PCMB in CBSE is not that bad. For you the career options are countless. You might go opt the following:
1. Engineering (Stream can be chosen according to your interest)
2. Medical Field (MBBS or BMS)
3. B.Sc. (Again stream to be chosen according to your interest)
4. Law (if interested)
Other than that if you want to choose any you can.
In the end you have to decide what your interest lies in.

There is no problem with you pursuing B.Com and MBA after that. You can definitely proceed with the same, but it will be a little difficult for you to catch up as compared to the Commerce students. But, since you seem interested in the course you might catch up fast, if you put in a little bit of extra effort.

It depends on your category. Suppose you are from general category your chances in the fifth round are also less. You may get the seat. As this years cut-off are yet be revealed, cannot say that you will definitely get a seat. If you belong to SC ST PWD your chances are higher.

Hi,
You will be having many opportunities You can go for engineering. or you can go with B.Sc. after that u can go with research field

It is really very easy to recover your missed chapters. You just have to be mentally focused and firstly, just start reading your chapters and if you are stuck with any doubt you can consult anyone as nowadays there are many ways such as YouTube and even at Shiksha.com you can ask questions as per your doubts, just thinking about your problem would not work out rather, you have to stand straight and face it. At least start reading the missed chapters first.

You should take biology in class 12th (PCB) and go for some course related to environmental studies.

You should go to Calcutta. It will be the best place for you.

Hi Ranajit,
Your only option under DU would be the SOL as cut-offs for regular courses are generally more than 90%.

Hi,
Follow these steps:
1. Learn all formulae from each chapter
2. Take previous years paper and practice them diligently
3. Manage your speed by doing mock tests
4. Stick to your text books.
Since you have got only one chance now, study hard and stick to your routine. Don't forget to relax as well. Best of luck.