hi,

the courses you have mentioned is quite different to each other, while forensic science is a combination of life science, physics, chemistry , modern techniques etc. besides the educational eligibility criteria candidates must have string analytical skill, problem solving passion, ability to work for long hours, team work ability etc. forensic science mainly involved with criminology and cases, in india you have to do masters courses along with bachelors to get a job in appropriate domain. however the job recruitment in india  on forensic department is not huge compare to other fields of study like llb, accountancy, mbbs etc.

now coming to b.sc in biotechnology course, this is also three years course, biotechnology is an interdisciplinary domain with deals with bio molecular substance, virus and genome structures, vaccination process etc. you have to do m.sc course in biotechnology to get job as quality assurance domain in industry.besides this biotechnology is mainly a research oriented fields and it is expected that in coming years demands for bio technologist would increase for food processing, medicine making , vaccine production like domains.

so you have to decide which area you are finding more interesting. from jobs prospect I would prefer to b.sc in biotechnology course over forensic science.