Science

Studies in Botany by JN Mitra, D Mitra and SK Chowdhuri, Vol. I:
Botany for Degree Students: Algae by BR Bashishta, Dr. AK Sinha and Dr. VP Singh
For detailed studies of the course content, Id suggest to go for topic wise published books. In this case, all books published by S CHAND GROUPS are the best with multi-color diagrams and detailed analysis of the topic.
All the best.

If you are not interested in medical then u can opt for these :-
1) Biotechnology
2) Microbiology
3) Pathology
4) Agriculture
5) Zoology/Botany .
All the best.

Hi
Check here about the distance mode courses in agriculture but before applying, ensure that its recognised by UGC.
http://www.indiaeduinfo.com/distance education/agriculture.htm

Hi
If you hv keen interest in computers, programming, softwares etc then go for bca. B.sc in any of the core subject will lead to either msc or mba mainly. There are many pg diplomas available. With B.Sc you hv variations like electronics, astrophysics, astronomy etc for higher studies and go for research too.
Hope this helps

While the course structure for both might be same the difference is of diploma and degree and degree always have more value in india atleast. Some of the best one who offer this course are NIFT, IIFT, Pearl Academy etc. You may search for more here.
https://retail.shiksha.com/merchandising-management-in-maharashtra-categorypage-11-46-1-0-0-1-114-2-0-none-1-0

after 12th u can go for NDA exam.nd after bsc u can go for CDS and OTA for both technical and non tech fields.
u cannot simply ask for a high office rank.ur experience in army and passing internal examination will give u a higher position in armed forces.
u can go for OTA(officers training academey) for 10 years of service