You may use information from the lectures and labs, but in general you will want to do some research either in the library or on the web to get the information you will need to write your essay. For each essay there is an assigned topic, followed by several questions. Your essay should address the topic, and you should be guided by the questions, but your essay should not be simply a series of answers to the questions. You do not need to answer all the questions, and you may use any format you like, e.g. a fictional story about the disaster caused by an asteroid hitting the earth would be acceptable, if it included the relevant information. I strongly suggest that you have someone else read a draft copy of your essay and give you feedback in order to make revisions.
First drafts are unlikely to satisfactorily meet the grading criteria.
You must include your references too. Earth Impacts as a Threat to Civilization Discuss the likelihood of a large meteoroid hitting the earth during your lifetime. Now extend your time horizon to ten thousand years, and discuss the largest impact we are likely to have in that period. Be specific about the probability per year of having such an event occur and what its impact on the Earth's environment would be. Do not discuss the make up of meteoroids, comets or asteroids, although you should understand what they are for the essay.