B.Sc

Most of the USA universities eligibility criteria is 10+2+4 years of education for seeking admission in MS. Therefore, you will not be eligible for MS in majority of USA universities. You are advised to do one year PG Diploma after B.Sc to meet the eligibility criteria for seeking admission in MS.

B.Tech deals with technology or technical bases things. B.Sc comes under Science streams like Chemistry, Botany, Zoology, Agriculture, Horticulture, Fishery, Dairy Farming, Forestry etc.

If you are interested in engineering field, then go for B.Tech.
If you are interested in Science stream means go for B.Sc. Both have good scope. All courses are good. Select what you want to do.

Of course. Any graduate can join for MBA program. After B.Sc in medical subjects, its better to do MBA in Healthcare Administration / Hospital Management. That will help you to find key roles in corporate hospital sector as Administrator, Senior Administration Managers, Healthcare Supervisors, DGM / AGM - Hospital Administration, etc.

After completing, you can either go for higher education and go for M.Sc. You can also look for MBA or prepare for banking exams and target SBI-PO/IBPS exams.

Depends upon the college's or university's rules. Check out which college you want to join. You can get full information. Majority of the colleges check your class 12th marks.