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.

Explanation

• Apollo 17 was the manned spacecraft that took humans to the moon.
• Apollo 17 was the sixth and final Apollo mission to land on the Moon.
• It was crewed by astronauts Eugene Cernan, Ronald Evans, and Harrison Schmitt.

Explanation

Direct current is produced when electrons flow constantly in one direction.

It's abbreviated as "DC".

Since direct current flows in one direction only, its electrical pressure or voltage is always oriented in one direction, or "polarity".

Explanation

Electronics is the branch of science that studies the flow and control of electrons, especially in circuits.

It uses active devices (like transistors and diodes) to control electron flow through amplification and rectification.

Explanation

Explanation

Explanation

• The renal artery is a blood vessel that carries oxygenated blood from the heart to the kidneys.
• It supplying them with the necessary blood flow to filter waste and excess substances from the body.

Explanation

The cranium is the bony structure that encloses and protects the human brain.

It is also known as the skull.

It forms the upper part of the skull.

It providing a protective casing for the brain.