a set of animal organisms in which the members have similar characteristics to each other and can breed with each other

a substance that makes something less pure or makes it poisonous

any of the materials such as water, coal, and wood that exist in nature and can be used by people 

a layer of air containing ozone high above the earth that prevents harmful ultraviolet light from the sun from reaching the earth

farm land which is used to meet the feed requirements of livestock, and which the owner has set aside for that purpose or which has been used for that purpose with the permission of the owner