SAT English Practice Question

As the planet's orbit carries it closer to the sun, the amount of light and heat received by Earth increases, and the Earth's climate shifts dramatically. The process of Earth’s shifting from warmer to colder climates, and back again, is known as the Quaternary Ice Age. During an ice age, glaciers grow and expand, covering large areas of the planet, but between ice ages, glaciers melt and retreat.

1. A.The process of Earth’s shifting from warmer to colder climates, and back again, is known as the Quaternary Ice Age—during an ice age, glaciers grow and expand, covering large areas of the planet.
2. B.The process of Earth’s shifting from warmer to colder climates, and back again, is known as the Quaternary Ice Age; during an ice age, glaciers grow and expand, covering large areas of the planet.
3. C.The process of Earth’s shifting from warmer to colder climates, and back again, is known as the Quaternary Ice Age; glaciers grow and expand, covering large areas of the planet, during an ice age.
4. D.The process of Earth’s shifting from warmer to colder climates, and back again, is known as the Quaternary Ice Age, during an ice age, glaciers grow and expand, covering large areas of the planet.