Frankly when I went college I chose to do most of my research on reptiles a decade ago, not even that long, meant that there was very little to be found on the internet or in libraries for specific medical conditions. And yet I managed it. I love this forum because veterans here get really specific and that's great when I have problems that directly affect the care of my horse. BUT if, based on your thread history, you are seeking answers to help do your homework then that's either pure laziness or fear of failure. At the end of the day the sorts of questions you are being asked above are to prove that you are using your brain to seek answers not necessarily the answers themselves. You can find information on the internet and in books but YOU have to compile it. Find a couple examples of the above scenarios and use them. Instead of typing your questions as they are why don't you pretend you are the owner of a yearling and type in google "can I keep my yearling alone?". I've just done that and there are TONS of threads to go through with plenty of people describing behaviour issues or pros for it. Use them as specific examples; it is not recommended to keep a yearling alone because XY, however scenario Z is an exception.
I think that you know more than you give yourself credit for and maybe the issue lies more with putting down your thoughts on paper. But you have to do it. I didn't like doing it when I was 16 because I thought my writing was crap but the fact you do it yourself speaks more than a plain cheater. Practice now! Good luck :)