Please hurry I have 5mins left Which pair of elements can be used to determine the age of a fossil that is over one billion years old?

A. lead, which is radioactive, and uranium, which is stable

B. carbon, which is radioactive, and nitrogen, which is stable

C. argon, which is radioactive, and lead, which is stable

D. potassium, which is radioactive, and argon, which is stable

Which of the following describe the role a biochemical pump plays in active transport? a it prevents water from moving across the cell membrane. b it uses energy to move materials across the cell membrane against the concentration gradient. c it large molecules cross the cell membrane without using energy. d it a cell move molecules from an area of higher concentration to an area of lower concentration.