Answer :
To address the question of how the thickness of Earth's atmosphere compares to the Earth's radius, let's analyze the given options:
The Earth's radius is approximately 4,000 miles. This measurement is the distance from the Earth's center to its surface.
The Earth's atmosphere is roughly 300 miles thick. It's important to note that the predominant part of the atmosphere's mass is concentrated within the first few miles, with the Troposphere, where weather occurs, stretching up to about 7 miles.
Considering these measurements:
(A) Greater than 4000 miles is incorrect. The thickness of the atmosphere does not exceed the radius of the Earth.
(B) Approximately 4000 meters is also incorrect. While 4000 meters (~2.5 miles) could represent a portion of the atmosphere, it doesn't summarize the complete atmosphere's thickness.
(C) Less than 4000 miles is correct. The overall thickness of the atmosphere at about 300 miles is significantly less than the Earth's radius.
Therefore, the correct answer is (C) less than 4000 miles.
