(1) Earth is surrounded by a thick gaseous envelope called the atmosphere. (2) The atmosphere provides the air that we breathe and protects us from the sun's intense heat and dangerous radiation. (3) The energy exchanges that continually occur between the atmosphere and space produce the effects we call weather. (4) If, like the moon, Earth had no atmosphere, our planet would be lifeless, and many of the processes and interactions that make the surface such an energetic place could not operate. (5) Without weathering and friction, the face of our planet might more closely resemble the lunar surface, which has not changed much in nearly three billion years. Question 10 options: a. The atmosphere is a thick gaseous layer covering the entire Earth. b. The moon, unlike Earth, has no atmosphere and has therefore not changed much in almost three billion years. c. There are many influences on Earth's development. d. The atmosphere is a key part of our environment and of Earth's processes.