Explanation

• Only about 2.5% (3%) of the water on Earth is freshwater, which is vital for human consumption, agriculture, and ecosystem health.
• The remaining 97.5% (97%) is saltwater, found in oceans, seas, and salt lakes.

Explanation

• Short-sightedness (myopia) can be corrected by wearing a concave lens.
• It is thinner in the center than at the edges.
• This lens disperses light rays, allowing them to focus correctly on the retina.

Explanation

The skin is considered the largest organ of the human body.

It covering an area of about 1.5-2 square meters (16-22 square feet).

It weighing around 3-4 kilograms (7-9 pounds).

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