Discuss the difference in the densities of the two types of Earth's crust. Why are they different?

Which of the following words describe the reality that the universe looks the same from various perspective

Which statement is true about the model of the electromagnetic spectrum a: it change the frequencies of light. b: it compare wavelengths of light. c: the color of light waves can be changed using the model. d: the intensities of light waves can be decreased using the model.

What is the best describtion of the side of the moon that faces earth?