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. 

Bmust be the answer, as technically all organs move, so a is incorrect. all organs are made of different types of cells, so that isn’t a problem, so c is also incorrect. human hearts are very similar to many other animals’ hearts, so d is also incorrect, yet the heart is made of muscle, which is hard to grow in the lab so it would be correct to say b