Answer:

A considerable number of individuals have take only vegetarian diets, because their belief they believe is that it helps to improve their health and thatthey also it affects positively to the betterment of the wold altogether. believe that it will help to benefit the world 

Some people prevent abstain from having eating meat or fish as there can may be various cancer-causing toxic toxins in them. While, others don't, eat non-vegetarian food as it can causes acne and or increase their cholesterol levels. Though there are such health benefit on one hand, there is no way for them to get nutrients, such as animal protein, that are essential for the growth of human body on the other hand.  Though there may be health benefits on one hand, their diet is lacking of nutrients such as animal-based proteins which are essential to maintain the health of the human body. 

Recent research shows that the greenhouse gas emissions, for example, carbon dioxide, has increased due to the mega large-scaled farms where cows, chickens, etc. are bred to produce meat, Ultimately, which, in turn contributes to the global warming. So, in a way, there are negative environmental impacts on environment, which can could be avoided if people change their eating habits. That is to say, being vegetarian is an environmental friendly habit.

My perspective on this is that it is each person's responsibility to decide whether to be a vegetarian or not n-vegetarian. If one prefers to eat meat or fish, there should be no restrictions, but he/she they should be aware of the consequences mentioned above.

I'll correct the 2nd part below due to character limit.