Gas molecules absorbing thermal infrared radiation and present in large quantity to change the climate system is known as

The correct option is greenhouse gases.

Step-by-step Explanation:

1. Understanding the Mechanism of Heat Trapping:
Solar radiation from the Sun passes through the Earth's atmosphere and warms the surface of the planet. In response, the warmed Earth emits energy back toward space in the form of longer-wavelength thermal infrared radiation (heat).

2. The Role of Greenhouse Gases:
Greenhouse gases (such as carbon dioxide, methane, water vapor, and nitrous oxide) possess a molecular structure that allows them to absorb this outgoing thermal infrared radiation. Instead of allowing the heat to escape directly into space, these gas molecules absorb the energy and re-emit it in all directions, including back down to the Earth's surface.

3. Climate System Impact:
When these gases are present in large quantities, the heat-trapping effect is intensified. This leads to a net increase in the Earth's average temperature, a phenomenon that drives global warming and significantly alters the global climate system.

4. Why other options are incorrect:
- Alpha radiations and Beta radiations are streams of high-energy particles emitted during radioactive decay, not atmospheric gases.
- Ozone is a specific greenhouse gas, but "greenhouse gases" is the comprehensive and correct general term for the group of gases that absorb infrared radiation and impact the climate system on a large scale.