Explanation

An Analgesic is a class of medication designed specifically to relieve pain

Explanation

Calculating the radius of the earth over a thousand years ago required a lot of imagination.

The 10th-century Persian mathematician Abu Rayhan al-Biruni used simple trigonometric results to estimate the radius and circumference of the Earth

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Explanation

A lead-acid battery consists of a negative electrode made of spongy or porous lead.

The lead is porous to facilitate the formation and dissolution of lead.

Explanation

Vaccines work by introducing a harmless version of a germ (an antigen) into the body to trigger an immune response.

The immune system then produces antibodies that will protect the body if it is ever exposed to the full-strength pathogen in the future.

The specific type of vaccine determines the form of the antigen used:

• Live-attenuated vaccines contain a weakened (or attenuated) form of the germ.
• These typically provide strong, long-lasting immunity with just one or two doses.
• Inactivated vaccines use the killed version of the germ.
• These often require multiple doses over time to maintain immunity.

Explanation

James Watt, a Scottish engineer, patented improvements to the steam engine in 1781.

He significantly enhancing its efficiency and power, and revolutionizing industry and transportation.