Which of the following statements best summarizes the main points of the passage? A There are three types of plate boundaries: divergent, convergent, and transform. B In 2011, an earthquake measuring 8.9 on the Richter scale shook the ocean floor. It made a giant wave which grew up to 30 feet (9.14 meters) tall. C Tectonic plates have always moved and always will. D Scientists study plate boundaries in order to understand tectonic movement, understand more about how plate movements can result in earthquakes, tsunamis, and volcanic eruptions, and explore how to predict these events.

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day

the doppler effect is used by weather forecasters to measure 

moving clouds