So the frequency is f =10 cycles / 120 s = 0.0833 cycles/s. Answer: D. Frequency refers to the number of occurrences of a periodic event per time and is measured in cycles/second. In this case, there are 10 cycles per 2 minutes (also known as 10 cycles per 120 seconds).
From the scientific viewpoint, the Earth would have had to form about 4.54 billion years since the earliest material in the solar system is dated back to about this time period.
The widely accepted theory of how Earth was formed nearly 4.50 billion years ago is by core accretion. Earth's rocky core formed first, with heavy elements colliding and binding together. Dense material sank to the center, while the lighter material created the crust. Gravity captured some of the gases that made up the planet's early atmosphere. The planet's magnetic field probably formed around this time.