all of the following are explanations for glacial periods EXCEPT.
a. varying solar energy
b. volcanism
c. biological organisms
d. Earth's orbit's precession
Volcanoes might end an ice age.
This might be of interest:
http://news.sciencemag.org/earth/2012/07/did-marine-snot-cause-ice-ages
To determine which of the given options is not an explanation for glacial periods, we need to understand what glacial periods are and the factors that contribute to them. A glacial period, also known as an ice age, refers to a period of time when the Earth experiences extended periods of cold climate and large ice sheets cover significant parts of the planet's surface.
a. Varying solar energy: Changes in solar energy, such as variations in solar radiation or solar activity, can influence the Earth's climate. These variations in solar energy can affect the temperature of the planet and contribute to glacial periods. Therefore, this is a valid explanation for glacial periods.
b. Volcanism: Volcanic activity can release large amounts of volcanic ash, gases, and aerosols into the atmosphere. These volcanic particles can act as a barrier and reflect sunlight back into space, thereby reducing the amount of solar radiation reaching the Earth's surface. This can lead to a decrease in temperature and potentially contribute to glacial periods. Therefore, this is a valid explanation for glacial periods.
c. Biological organisms: This option seems unrelated to the mechanism behind glacial periods. Biological organisms are not typically considered as primary factors for causing glacial periods; it is other natural forces that play a more significant role in shaping Earth's climate. Therefore, this is likely the correct answer since it does not explain glacial periods.
d. Earth's orbit's precession: The planet's orbit around the Sun is not a perfect circle, but rather an elliptical shape. Over long time periods, the orientation of Earth's orbit changes, and this change is known as precession. The precession of Earth's orbit affects the distribution and intensity of sunlight received at different latitudes throughout the year. This variation in solar radiation due to precession can impact the climate and potentially contribute to glacial periods. Therefore, this is a valid explanation for glacial periods.
In conclusion, the option that is not an explanation for glacial periods is c. biological organisms.