Explanation

Decibel (dB) is the unit used to measure sound intensity.

Which is related to the amplitude of a sound wave.

The amplitude of a sound wave determines the loudness of the sound

One decibel (0.1 bel) equals 10 times the common logarithm of the power ratio.

Explanation

China has successfully landed a robot on the surface of Mars on 15 May 2021.

China has become the third country after Russia and the United States of America in history

The rover 'Zhurong' will spend around 90 Martian days on the planet.

A Martian day is around 24 hours and 39 minutes.

This rover is named after the mythical Chinese god of fire.

Explanation

Explanation

The planet that revolves the slowest around the Sun is Neptune.

It takes Neptune approximately 165 Earth years to complete one orbit around the Sun.

This slow movement is due to Neptune's large distance from the Sun, which is nearly 4.5 billion kilometers.

Neptune is the farthest planet.

It was visited by the spacecraft Voyager 2.

It's is a very windy place.

It has six rings.

It has 14 moons.

Explanation

Lead is commonly used in lead-acid batteries, which are widely used in automotive applications and for backup power systems.

Lead-acid batteries are known for their reliability and relatively low cost. 

Explanation

Robert Brown discovered the nucleus in plant cells.

It was first described by Franz Bauer in 1804 and in more detail in 1831 by Scottish botanist Robert Brown.

Explanation

The universe is 13.7 billion years old with an uncertainty of 200 million years.

The WMAP model assumes that the universe's energy is made up of: 70% dark energy, 26% cold dark matter, and 4% atoms and photons

Explanation

A microscope is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. 

Explanation

Bile is produced by the liver and stored in the gallbladder.

It is important for the digestion and absorption of fats in the small intestine.

Explanation

Snails are mollusks, belonging to the phylum Mollusca.

They typically have a soft body and, in many cases, an external shell.