Answer:
A. Scientists think that Earth's orbit can play a role in the onset of an ice age because it affects the amount of solar radiation that reaches different parts of the Earth's surface. Specifically, variations in Earth's orbit can lead to changes in the distribution of sunlight, which can influence the temperature and precipitation patterns that are necessary for the growth and retreat of glaciers.
B. Precession is a term used to describe the slow, cyclical wobbling of Earth's rotational axis. This wobbling causes the direction that the axis is pointing to slowly shift over time, completing one full cycle approximately every 26,000 years.
C. Precession is related to an ice age because it can affect the timing and intensity of the seasons, which in turn can influence the growth and retreat of glaciers. During certain phases of precession, the Earth is closer to the Sun during the summer in one hemisphere and farther away during the winter, which can lead to more extreme temperature and precipitation patterns. These patterns can create conditions that are more favorable for the growth of glaciers, which can contribute to the onset of an ice age.
Step-by-step explanation: