One of the most important decisions thathumans have to take is to choose his living place, where he can feel more comfortable.
human has to make / humans have to makeIt is argued that people opt to live in big cities rather that small town or villages.
... this slightly deviates from your topic. It does not say that people prefer living in big cities over small towns. What it says is that some love to live in cities while some prefer small towns. It is important that you always go with your topic keeping a proper alignment. If you interpret your topic differently, then you would be in trouble.
Big cities have a bigger market, wider commercial area and thus better work opportunities. For example, one of my friends who was living in a village in Saudi Arabia, had a good voice and was singing in wedding parties. But when he moved to the capital Riyadh he published his first song album in only 1.5 years. From this example we can see that there are more activities in cities that help people toexpose their giftsexplore and grab opportunities. It is clear from the example that we can have better opportunities in big cities .
... this is a fine reason and very good example. The last sentence is a repetition of the same idea again. Avoid repetition.
However, as you already mentioned this is too short and you need to have a minimum word count requirement. Also, your essay should contain two body paras and this has got only one.