Explanation

• The kidneys are the primary organs responsible for removing waste and excess substances from the body through urine.
• They filter the blood and regulate electrolyte levels, playing a critical role in maintaining overall bodily function.

Explanation

• Red light has the longest wavelength, approximately 620-750 nanometers (nm).
• While violet light has the shortest wavelength, approximately 380-450 nm.
• The order of colours in the spectrum, from longest to shortest wavelength, is: Red, Orange, Yellow, Green, Blue, Indigo, Violet (ROYGBIV).

Explanation

• The stratosphere is the layer of the atmosphere where the ozone layer is present.
• It extends from approximately 12 to 50 kilometers (7.5 to 31 miles) above the Earth's surface.
• The ozone layer is a critical component of the Earth's atmosphere, as it absorbs harmful ultraviolet (UV) radiation from the sun, protecting life on Earth.

Explanation

• A barcode reader, also called a price scanner or point-of-sale (POS) scanner.
• It is a hand-held or stationary input device.
• It used to capture and read information contained in a barcode.

Explanation

• The ozone layer in the stratosphere absorbs and restricts ultraviolet (UV) radiation from the sun.
• It protecting life on Earth from harmful UV rays.

Explanation

• The Mole (mol) is the SI unit of amount of substance, representing 6.022 x 10^23 particles.
• It is used to measure the amount of a substance in a sample.

Explanation

A reaction in which heat is absorbed is called an endothermic reaction.

These reactions lower the temperature of their surrounding area, thereby creating a cooling effect.

Explanation

• When blue litmus paper is dipped in an acid, it turns red.
• This is because the acid changes the color of the litmus paper from blue to red.

Note: When red litmus paper is dipped in a base, it turns blue.

Explanation

• The greenhouse effect is an environmental problem caused by the increasing amount of carbon dioxide (CO2) in the atmosphere.
• Primarily due to human activities such as burning fossil fuels, deforestation, and land-use changes.
• This excess CO2 traps heat and leads to global warming and climate change.

Explanation

• Phenolphthalein is a pH indicator that changes color in response to changes in acidity or basicity.
• In an acidic medium, it is colorless, and in a basic medium, it turns pink.