"Trading or Advertising" are two very different and very broad career catagories. Without any experience it can be hard to break into any career field, especially if you don't even know what you want to do in that field. Do you have your own trading accounts? Have you had an success? That might be a way to start to break in.
With a Bio degree, and no experience in the fields that you like, it is going to be hard to "break in". I mean, how much do you even know about advertising or trading? And how do you actually know that it's what you want to do? There are so few people that actually "trade" for a living, and even fewer that do this right out of school. Normally someone works for a company that does some type of trading or investing, and these are extremely tough careers to get into (think Ivy League).
Advertising on the other hand can be a little easier, but it depends on where/what you work in. But honestly, with no experience, what value would you bring to a company? Are you an expert designer or graphic artist? Do you understand marketing principles, market studies/research, or all the different areas of advertising. It's easy to think advertising is "creative" but in fact there are tons of business prinicipals and boring work that goes into any marketing or advertising campaign. To get into a "creative" position requires skill, hard work, and luck.
All this being said, you need some more education or excellent networking skills to even have a shot to get into one of these fields. And with the fact that you can't self motivate yourself to study for the GMAT makes it hard to think that you will self motivate yourself towards your career goals. You have to be 100% committed to get the most out of any school program, and it might be smart to start figuring out more of what you want to do.
I'd recommend contacting your college and seeing if you can see a career couselor. See if they can offer any help. And if not, you need to decide what you really want to do. THen committ 100%. Join networking clubs for that area, try to take classes or get into a school that will help you in that direction, try to find a mentor, network with family and friends, and don't stop until you know exactly what you want to do and get there. For experts in any career field, anyone that comes in and says "I want to do trading" will immediately know that you don't know what your talking about. Learn the field, live the field, and don't stop until you get where you want to be. Even with top education, no one will give you your dream job. It takes hard work and dedication.
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