a word governing, and usually preceding, a noun or pronoun and expressing a relation to another word or element in the clause

African penguins, which inhabit the coasts of southern africa, were classified as an endangered species in 2010. two significant threats to their survival are ecosystem damage from oil spills and overfishing by humans. overfishing depletes the food supply of african penguins. the best method to reduce the threat of overfishing would be to . the risk of oil spills could be reduced by increasing the use of , which should oil consumption. if an oil spill does occur, could be used to remove the oil so the ecosystem may more quickly recover.

The mixture of sperm and fluids from the seminal vesicles, prostate gland, and cowper's glands is called

The law of thermodynamics states that energy can't be created or destroyed. to natural sources of energy on earth are the