In this creation, every individual should depend on other living organism. So we kill them, we use them. Even if we are vegetarians, we have to kill plants for the sake of food and silkworms for the sake of cloths. Food and clothes are basic needs. We cant avoid them. Not only we, but also all organisms living on this earth including small microbes cant avoid killing higher organisms by infecting. Why cant we live without harming other organisms? Why cant we have some food source other than living things? Can every organism live by using some nonliving thing as energy source? There is an interesting answer to this question. According to science, things which can grow, respond, reproduce are considered as living things.
If creation is in such a way that every organism can live by eating non living things like rocks, mud,etc.., it will lead to the end of the life on earth within few days after creation. The reason is, the organisms which take birth after formation of earth will eat away all the non-living things present on this earth. Then there wont be any food source left. Therefore living organisms will starve and they will die soon. This leads to end of the life on earth. So if life has to be there on this earth forever, the things which living organisms eat should have capacity to grow simultaneously along with the consumers. But according to definition, the things which can grow, reproduce are living. So living organisms should use other living organisms as their food source. So finally it is true that creation is very clever!!!