I hope there are not plenty of mistakes
...Nowadays, we face to plenty of disasters
The word "plenty" is not the same as many, but the way you use it makes me think you believe it is the same as many. Actually, we use plenty to mean we have more than we need, but we usually do not use it to talk about something we do not want. So, use "many" instead of "plenty" when you talk about bad things.
The answer is, of course, "yes," due to fact that nobody can know future. To give an ...
Owing to fact that any of us could be a disaster victim, we must donate.
What is more, we donate not only money but also our organs, such as, kidneys, livers, etc. Therefore, an ailing person can be cured with the use of our organ donation.
I wonder how I will finish this exam more impressive
just keep collecting good phrases. You already have a good vocabulary, but read a little every day and memorie one great new way to say something you need to say. You write very well, very clearly, even if there are some errors.
:-)