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.

Explanation

Ebastine is a non-sedative H1 antihistamine that blocks the allergy-causing receptors.

It is an anti-allergic medication that cures allergy symptoms, such as sneezing, itchy eyes, runny nose, skin rashes, red eyes, and other symptoms.

Ebastine is an effective treatment for both perennial and seasonal allergic rhinitis.