Answer is D.
The ECG picks up electrical activity (action potentials) in the heart.
Galapagos island was an island ecosystem. It has many unique features of its own. Their equatorial position on the globe in complementary with its location made the climatic conditions feasible for the species to survive and evolve there.
It has a mix of both the tropical and temperate there which favored the growth of unusual plant species there. Due to these plants species there evolved many reptiles species , birds species and some mammals.
