Botany

Yes, Dyal Singh College has B.Sc. Hons in Botany course. As Dyal Singh college comes under University of Delhi, so take admission in this college. You have to first fill the registration form for Delhi university (DU) and then wait for the release of cut offs and then you can apply for the admission in Dyal Singh college on basis of your 12th score only if you met their cut-off requirement. For more details about Dyal Singh College, refer to the following link:
https://www.shiksha.com/college/dsc-dyal-singh-college-lodi-colony-Delhi-2319.

Yes Ankit, you can. For more conformation, contact the management or lecturer of your B.Sc college/ university.

You have passed HSC (with Biology) with good score, so getting admission into the B.Sc (Botany or Zoology) is possible. But, Admissions in the college depends upon the current year demand for the course. Best of Luck.

You have passed B.Sc (with Chemistry, Botany & Zoology), so it is a Graduate Degree programme in Life Sciences, which is eligible to apply for the Admission in the M.Sc (Diabetes & food nutrition).