How long do anxiety disorders last?
a. at least one year
b. at least six months
c. at least six weeks
d. at least two years

As experience, none of the options are correct.

If you have relatives that suffer from anxiety, even the slightest bit, you are likely to have it some point in your life. How severe or moderate the anxiety is, I can inform you that once you get it, you will continue to have it throughout your life-time. There is no medicine or cure for anxiety, as it is just a fear and you have to control your mind when it comes. Half of the population has some sort of anxiety disorder, whether it be social anxiety, etc. Until you learn how to deal with whatever is making you anxious and to have anxiety, it will be there forever until you know how to deal with it, although, that rarely happens. Even if you find out a way to deal with it, you are still likely to get small pop-ups of it. If you DO find a type of pill/medicine that helps with the anxiety, you are surely to still have small bursts of it. Anxiety can make you feel like you are dying, or something bad is happened. It sucks, yeah, but there is no period for it. There is no, "oh, only 3 more months till my anxiety disorder clears!" No. People who suffer from it probably wish that, but sadly it doesn't work like that. 

To sum it up, your options are wrong. None are correct. You should probably inform your teacher or instructor that they got incorrect information, and that people suffering from anxiety can go their life-time with it. 

Because without physical activity, the body has extra "energy" if you will, and so when it is time for bed you are not tired, so you end up staying up all night. also there is probably an effect on your internal clock, which messes with your melatonin production which goes hand in hand with your sleep cycle

The answer would be d. most contraceptives are effective when used properly