7.(05.02 MC) The speed of light in four different materials is shown below:
Material Speed of light in thousand miles per second
A
140
B
78
С
186
D
12
Which material is the most dense? (4 points)
Material A
Material B
Material C
Material D

Which of these statements describes the size of an atom? a. an atom is larger than a sheet of aluminum foil. b. an atom is small but can be seen with just our eyes. c. an atom is the size of a plastic building block. d. an atom is tiny and cannot be seen without magnification.