Explanation

• The audible range of a normal human ear is typically considered to be between 20 Hz (very low frequency) and 20,000 Hz (very high frequency).
• This range encompasses the vast majority of sounds that humans can perceive, from the lowest rumble to the highest pitch.

Explanation

Global warming is primarily caused by the increasing levels of carbon dioxide (CO2) in the Earth's atmosphere, which traps heat and leads to a warming effect.

The main reason for this increase is human activities such as:

• Burning fossil fuels like coal, oil, and gas
• Deforestation and land-use changes

Explanation

ICT is a term for information technology that stresses the role of unified communications and the integration of telecommunications.

ICT stands for Information and communications technology

Explanation

Explanation

The stratosphere is the second layer of Earth's atmosphere as you go upwards, lying above the troposphere and below the mesosphere.

The layers of the Earth's atmosphere, in order from the surface, are:

1. Troposphere (up to about 12 km/7.5 miles)
2. Stratosphere (up to about 50 km/31 miles)
3. Mesosphere (up to about 85 km/53 miles)
4. Thermosphere (up to about 600 km/373 miles)