tman

I know that 99.9% of the human genome is the same for all humans. So irregardless of your race there is very little genetic variance. Obviously the differences in groups of people, color of skin, hair type, etc. are genetically based since they are apparent in subsequent generations. I couldn't say how many of the differences in races are genetically based and whether some of these differences are based on the way you were raised. In comes the nature vs nurture debate.

Being in college right now I have realized that there is no reason to try and declare a major when you start and feel like you have to do that for the rest of your life. I am a junior and I know I want to go into a biology related field, however, I'm not sure which field interests me the most. I would suggest doing a lot of reading and take a broad selection of classes. This will help you to find things that interest you and identify the things you never want to think about again. Once you get interested in a certain field of study you can pursue it further. Take your time though, you have your whole life to make your descision. Most importantly, don't get caught up in what career will offer more money, prestige, or advancement opportunities. Theres nothing worse than spending the rest of your life doing something that doesn't make you truly happy.

Humans can have an extra chromosome and still survive. If nondisjunction occurs (which is the failure of 2 members of a homologous chromosome pair to separate during meiosis) you can wind up with one less chromosome or even an extra chromosome. People who have Down Syndrome suffer from having 3 copies of chromosome 21, one chromosome too many. Despite having serious health problems someone with Down Syndrome can live a long life.

Plants are capable of having stomata located on the top of the leaf. Some plants that live in water, known as hydrophytes, have stomata on the top of the leaf. Since the leaves float on water it would be impossible for gas exchange to occur if the stomata were located on the bottom of the leaf.