Clifford is an astronomer who studies the movement of stars. What types of tools does Clifford likely have in his office that help him study the movement of stars?

1) meter sticks and protractors
2) rubber bands and paper clips
3) rulers and measuring tapes
4)telescopes and cameras

Aneuron is stimulated with an electric pulse. the action potential is detected at a point 3.70 cm down the axon 0.0052 s later.when the action potential is detected 7.20 cm from the point of stimulation, the time required is 0.0063 s. what is the speed of the electric pulse along the axon? (why are two measurements needed instead of only one? )

An atom of nitrogen had seven protons in its nucleus. how many electrons does it have

Place the steps tor the formation of the enzyme pepsinogen in correct order