GED Science Practice

What is the atmosphere?

1. The whole mass of gases surrounding a planet

2. An upper chamber of the heart that receives blood from the veins

3. One of a group of "minor plants" between Mars and Jupiter

4. The joining of atomic nuclei to form heavier nuclei

The correct answer is: The whole mass of gases surrounding a planet

The atmosphere is defined as the whole mass of gases surrounding a planet. This includes various gases, such as nitrogen, oxygen, carbon dioxide, and others, that not only envelop the planet but also play crucial roles in supporting life, regulating temperature, and protecting the planet from harmful solar radiation. The atmosphere is also vital for weather and climate systems, allowing for the existence of various ecological and meteorological phenomena. The other options do not accurately describe the atmosphere. For instance, the upper chamber of the heart that receives blood from the veins pertains to anatomy, not the composition of planetary gases. Similarly, "minor planets" refers to celestial bodies in the asteroid belt, which is unrelated to the concept of atmospheric gases. Lastly, the process of atomic nuclei joining to form heavier nuclei relates to nuclear physics and fusion, again bearing no connection to the definition of an atmosphere.