You can apply for the Bachelor's Degree Programme (BDP) at IGNOU which includes the BSc programme. One such course is LSE or Life Science. You need to select elective courses in Life Science first.
IGNOU has a credit-based grading system. This requires you to complete 32 credits in a single academic year. This totals 96 credits in 3 years.
For the first year 16 credits will be from foundation courses. Other credits will be from your elective courses.
For a major degree you need to have 48 credits from the subject you wish to major in.
In the 3rd year it’s decided whether you have a BSc (zoo) or BSc (bot). This depends on the choice of your subjects.
BSc in Biology also required lab courses. These constitute about 25% of your marks and attendance is compulsory.
Take a second elective from the rest (maths, physics, chemistry) such that it carries at least 8 credits.
If you are still having difficulty understanding the credits visit the university’s official website.
It depends on what you are interested in and what career you want to pursue. My personal suggestion would be to make IIT Delhi your first preference.
First, if you are a civil services aspirant, get admission into IIT Delhi in any branch and prepare for UPSC through the various coaching institutes available.
If you are somehow not able to make it into IIT Delhi, then invest another year preparing for JEE and aim for a higher rank. Once you are able to make it into IIT Kanpur, again you need to work hard for one year to get a branch change into Civil. You will be competing with geniuses from CS and ME but keep yourself motivated. A CPI of 7+ will make it possible to get a branch change. Attend your classes regularly, complete your assignments on time and you are good to go.
Lastly, if you are unable to change your branch, go for pure sciences like Physics, Chemistry, BSBE, or Earth Science. Out of these Physics and chemistry have a heavy workload and it will be tough to cope with your batchmates. BSBE has pathetic placements. Another option is Earth Sciences which in my opinion is the best considering the light workload and job opportunities. The average CPI is lesser than other branches and most of its courses overlap with Civil Engineering. Basically, Earth Sciences is equivalent to Civil Engineering just without the Engineering element.