Essay: Using animals for the benefit of the human beings

With the rapid development of the standard of people's life, increasing numbers of animal experiments are done, new medicines and foods, for instance. Some opponents says that it is cruel to animals and nature, however, I believe that no sensible person will deny that it is a dramatically cruel activity to humanity if the latest foods or medicines are allowed to sold without testing on animals. In my essay, I will discuss this issue from twofold aspects.
First of all, as we all know, animals are friendly and vital for people, because if there are no animals in the world, the balance of nature will broke down, and we, human, will die out as well. The animal experiments accelerate the vanishing of some categories of animals. In other words, doing this various testing is a hazard of human's future and next generation.
Though animal experiments have negative impact on the natural balance, it is necessary to make sure that people can live a long life. To begin with, it is indisputable that every new kind food or pill may be noxious, and scientists must do something to insure that the new invention benefits people instead of making people ill or even dying. The new foods or medicines are invented to promote the quantity of human's life. Thus even if they are volunteers; they cannot take the place of animals to test the new foods or medicines. Furthermore, it also have potentially harm for human's health without any testing. 
To sum up, I reaffirm that although there is some disadvantages of animals' profits, the merits of animal experiments still outweigh the demerits.
Argumentative components: there is some disadvantages of animals' profits
the merits of animal experiments still outweigh the demerits
it is a dramatically cruel activity to humanity if the latest foods or medicines are allowed to sold without testing on animals
doing this various testing is a hazard of human's future and next generation
animals are friendly and vital for people
if there are no animals in the world, the balance of nature will broke down, and we, human, will die out as well
The animal experiments accelerate the vanishing of some categories of animals
animal experiments have negative impact on the natural balance
it is necessary to make sure that people can live a long life
it is indisputable that every new kind food or pill may be noxious, and scientists must do something to insure that the new invention benefits people instead of making people ill or even dying
The new foods or medicines are invented to promote the quantity of human's life
even if they are volunteers; they cannot take the place of animals to test the new foods or medicines
it also have potentially harm for human's health without any testing
Major claims:
the merits of animal experiments still outweigh the demerits
it is a dramatically cruel activity to humanity if the latest foods or medicines are allowed to sold without testing on animals

Claims:
there is some disadvantages of animals' profits
the merits of animal experiments still outweigh the demerits
it is a dramatically cruel activity to humanity if the latest foods or medicines are allowed to sold without testing on animals
doing this various testing is a hazard of human's future and next generation
it is indisputable that every new kind food or pill may be noxious, and scientists must do something to insure that the new invention benefits people instead of making people ill or even dying

Premises:
animals are friendly and vital for people
if there are no animals in the world, the balance of nature will broke down, and we, human, will die out as well
The animal experiments accelerate the vanishing of some categories of animals
animal experiments have negative impact on the natural balance
it is necessary to make sure that people can live a long life
The new foods or medicines are invented to promote the quantity of human's life
even if they are volunteers; they cannot take the place of animals to test the new foods or medicines
it also have potentially harm for human's health without any testing