Is radioactivity physical or chemical property?

Galileo was the first to notice that the moon has craters, valleys, and mountains. how might this have changed people's perception of the moon at the time?

Apebble is thrown into a calm lake, ripples are formed from the center and move outward. the water particles in the lake travel in a circular pattern that moves up and down on the surface of a lake, and the energy travels a) diagonally. b) downward. c) horizontally. d) upward.

True or false graphs must include scales that increase by the same amount