Hello Biswajit,

In NEET, only having the information needed to answer a question is not enough. There are a lot of factors which decide whether you would be able to score that many marks. There are 180 questions and there are 180 minutes. So you not only need to answer a question correctly and accurately, you need to do so with speed as well. 

So, practising lots and lots of MCQs and doing previous year question papers with a time limit is essential for being able to get the marks you want to score.

Moreover, just having the information related to a question doesn't necessarily mean that you will be able to answer a given MCQ. At times, a question may need you to think in a certain way and only then can you answer that question. By solving MCQs, you can develop that kind of perspective which will increase your speed and accuracy while answering a question.

Thank You

Biology: Read NCERT LINE TO LINE & memorise everything

solve a lot of mcq questions so that you can easily answer trick questions

physics: do ncert questions & then solve packages & previous year questions

chemistry: study ncert, do back questions from the book & practice MCQ to increase speed for solving. 

All the best