Author Question: Which of the following is true of wavelengths of signals sent into space? A) Wavelengths longer ... (Read 80 times)

cherise1989 · **on:** Jul 27, 2018

Which of the following is true of wavelengths of signals sent into space?

A) Wavelengths longer than 100 cm are absorbed in Earth's atmosphere.
B) The interval between the 21-cm spectral line of neutral hydrogen and the 18-cm line of OH has very high background interference.
C) Wavelengths longer than 100 cm get lost in the background noise of the Milky Way Galaxy.
D) The interval between the 21-cm spectral line of neutral hydrogen and the 18-cm line of OH is narrow and can be monitored easily.

Question 2

Which of the following is true of natural selection?

A) It is a random occurrence.
B) It does not occur in most species of organisms.
C) It is directed by changes in the environment.
D) It does not lead to evolution of a species.