Scientist use their knowledge of the half-life of carbon and uranium isotopes to measure the age of the rock or fossil .

List the two type of transporst that the cell in orde to transport molecules acroos the membrane

Astudent is asked to identify and element that is pale yellow brittle solid and does not conduct electricity. at which location in this periodic table would the element most likely be found?

Which class of molecules functions as chemical signals? hormones water carbohydrates proteins