Why do metamorphic rocks form at subduction zones?

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? )

Dna is colied into chromosomes in a cell

Name the types of burns one can get and which structures of the integument are damaged