Two points concerning the essay questions:

1.  I hope I don't have to read your essay question answers!

I only read them if you end up on the border between two grades.  If you end up with an overall average of 79.6% for example you would be on the C/B border.  Then I would read you essay question answers and try to use them to determine whether to give you a C or a B for the course.  If you do a good job on the essays I would give you a B.  If not you would end up with a C.  The essay question answers can only help raise your grade they won't lower it.  If you ended up with an 80.2%, you have a B.  I wouldn't put you on the C/B border, read your essay question answers, and then lower your grade to a C if you did a poor job or didn't answer the questions at all.

2.  Your answers don't really have to be in the form of an essay.

I try to make the questions pretty open ended.  Your goal should be to include as much relevant accurate information as you can.
Here's an example (this is also a good way to study the material in my opinion).

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Sample Question: Tell me everything you know about clouds.
The problem is always where to begin.

Once you have one idea down, others will follow:

I like seeing words like condenses, freezes, and deposition.  When does water vapor condense?

What causes air to rise?

By now you're starting to have quite a bit of information and you're just getting started.  You've saved the best for a second page:

You could perhaps add some written descriptions of the cloud types above.  This would make a very complete answer.  About the only other thing I could think of including would be the appearance of clouds on visible and infrared satellite photographs.