A federal mandate requires that drug tests screen for all five of these types of drugs. Time Frame Hair drug tests can detect drugs that have been in the system for 90 days, or three months. Considerations Many consider hair testing to be much more effective than urine testing because the results cannot be as easily tampered with. The hair test can also detect drugs that have been in the system for a much longer period of time than a urine test. Fact In order for the hair test to be accurate the sample of hair used must contain 90 to 120 strands of hair.
written for the kidsknowit network by brandon guymon there are three main types of rocks igneous sedimentary and metamorphic each of these types of rocks are formed in different ways and each type of rock can be changed into each of the other types of rockgeologists call this process the rock cycleessentially the rock cycle is the process that makes and recycles rocksritten for the kidsknowit network by brandon guymon there are three main types of rocks igneous sedimentary and metamorphic each of these types of rocks are formed in different ways and each type of rock can be changed into each of the other types of rock
Types of Rocks Rocks are not all the same! The three main types, or classes, of rock are sedimentary, metamorphic, and igneous and the differences among them have to do with how they are formed. Sedimentary Sedimentary rocks are formed from particles of sand, shells, pebbles, and other fragments of material.