Sorry I missed your essay -  I was looking for something else and just found it. Apologies. 

Everybody - please feel free to comment on other people's essays, especially if they look lonely!

Introduction

Your introduction is fine - you have given a definition, both sides of the problem, and a thesis sentence (what you will do in the essay). There are some errors in agreement and in plurals, and some unnecessary words. There is also some repetition:

Zoo is one of the main attraction site in urban areas. People visits this place to see animals and they want to learn about the behaviour and characteristics of the animals. However, animal rights group are againgst in keeping animals in the zoos. In this essay, I will discuss the arguments for and againgst keeping animals in zoos.

This could be rewritten as:

Zoos are one of the main attractions in urban areas. People visit to see animals and to learn about their behaviour and characteristics. However, animal rights group are against keeping animals in zoos.  In this essay, I will discuss the arguments for and againgst keeping animals in zoos.

There is some repetition here in the second and third sentences...'against keeping animals in zoos.' You only have 250 words and 40 minutes to show the examiner your vocabulary, so don't repeat if you have a good alternative!

In this essay, I will discuss the arguments for and against forcing wild animals to live in captivity.

Simplify and shorten

You have some words and phrases which could be simplified a little, and some unnecessary words - not wrong, just unncessary.

Rampant hunting and killing of animals can cause to lessen their population and might lead to extinction of its kind. In order to save those animals on the brink of extinction, some people tend to relocate or placed them on zoos to be secured. In this manner,  scientist can study the characteristics of a animals and save them from extinction. Other scientist try to help animals in the zoos to produce offsprings in order to increase their populatio. More than that, zoos charged admission fee; this profits will aid zoo owner to keep the animals well nourish or help researchers to improve their scientific studies on how to preserve and extend animals life. (113 words, average 22.5 words per sentence.)

Here's the paragraph slightly shortened. I've removed some unnecessary words, changed some word forms, kept it all in the present tense ("charged"), added and removed some articles ("the, a, etc") and changed some pronouns ("these profits"). 

Rampant hunting can lessen animal populations or even lead to extinction. In order to save animals on the brink of extinction, some people relocate them to zoos. In this way, scientists can study an animal's characteristics and help save them from extinction. Animals in zoos can produce offspring to increase their population. In addition, zoos charge admission fees, and these profits help zoo owners to keep the animals well nourished and researchers to improve their scientific studies (on how to preserve the animals' lives).  (77 words,  13 words average per sentence).

(I know what you mean about the scientists helping the animals to produce offspring -  they are helping in a scientific way, I'm sure. It's difficult to rewrite!)

Many writers worry about how they can reach 250 words if they have to remove words. Don't worry: be tough on yourself and get rid of all unnecessary words and phrases. Show the examiner the good stuff -  there's no need to say the same thing two different ways.

In Paragraph 3, watch out for prepositions and phrasal verbs

• stressed out ==> stress
• walking around on a limited space ==> walking around on a limited space
• depend to ==> depend on
• compared in ==> compared to/with

and watch out for run-on sentences. These are easy to fix - just make separate sentences OR join them properly to the previous sentence.

Their cages have a limited space compared in the wilderness lions can roam around freely and hunt their prey for food.Instead they are just walking around on a limited space and depend to the people who feed them

Their cages have a limited space compared with the wilderness, where lions can roam freely and hunt their prey. Instead they just walk around in a tiny space and depend on the people who feed them.

Conclusion 

Again, one or two words need to be removed just to tighten up your essay.

In order to prevent this situation happens, animals should be kept in a secured facilities which they can increase their population...

In order to prevent this situation, animals should be kept in secured facilities where they can increase their population...

Overall, your essay is clearly organized. It just needs some tightening up and some attention to detail -  watch pronouns, agreement and prepositions, and look out for words that you can remove.

    Rampant hunting and killing of animals can cause to lessen their population and might lead to extinction of its kind. In order to save those animals on the brink of extinction, some people tend to relocate or placed them on zoos to be secured. In this manner,  scientist can study the characteristics of a animals and save them from extinction. Other scientist try to help animals in the zoos to produce offsprings in order to increase their populatio. More than that, zoos charged admission fee; this profits will aid zoo owner to keep the animals well nourish or help researchers to improve their scientific studies on how to preserve and extend animals life.

   In contrast, animal rights group are against keeping the animals in zoos. They stressed out that animals should be in the wilderness, not in cages. Zoos are suppressing the freedom of the animals.Their cages have a limited space compared in the wilderness lions can roam around freely and hunt their prey for food.Instead they are just walking around on a limited space and depend to the people who feed them.

  In conclusion, animals have the right to live freely in the wilderness. However, due to the cruelty of mankind, some animals are destined to perish. In order to prevent this situation happens, animals should be kept in a secured facilities which they can increase their own population with the help of scientist.

Thank you for reading my essay, feel free to correct my essay.