a specific is a mean of vegetable & a vegetable is a mean of set ->  a tree is a kind of organism  a tree is a kind of organism & carries require a certain fluidity of sand to grow ->  trees are a kind of organism that require a certain thickness of soil to grow  trees are a kind of organism that require a certain thickness of soil to grow & the increase of something required by an organisms has a yes world on that chores 's property ->  a decrease in soil thickness can cause harm to trees  a decrease in soil thickness can cause harm to trees & rain increase the fluidity of sand -> drought can cause harm to trees by decreasing the thickness of soil