Explanation

• Down syndrome disorder is associated with chromosome number 21.
• It is a genetic condition caused by the presence of an extra full or partial copy of chromosome 21,
• Resulting in a total of 47 chromosomes instead of the typical 46.
• This condition is also known as Trisomy 21. 

Last updated question 28 feb 2026

Explanation

2H₂ + O₂ → 2H₂O

This balanced equation ensures 4 hydrogen atoms and 2 oxygen atoms on both sides.

It correctly represents the formation of water from hydrogen and oxygen gases.

Explanation

Gold is the most malleable metal, which means it can be beaten into thin sheets or shapes without breaking.

Gold is a soft, ductile metal with a high degree of plasticity, making it easy to work with.

It can be hammered, rolled, or bent into various forms without cracking or shattering.

Explanation

• Attenuation refers to the decrease in strength or intensity of a signal as it travels through a medium or is processed by a system.
• This can occur due to various factors such as resistance, impedance, or absorption, and can affect the quality and fidelity of the signal.

Explanation

Perseverance landed on Feb. 18, 2021.

 is a car-sized Mars rover designed to explore the Jezero crater on Mars as part of NASA's Mars 2020 mission.

It was manufactured by the Jet Propulsion Laboratory and launched on July 30, 2020

As of 23 July 2023, Perseverance has been active on Mars for 861 sols.

Explanation

The speed of sound in steel at 20°C is approximately 5100–5200 m/s, with 5130 m/s being a widely accepted value.

Sound travels faster in solids like steel due to their high density and elasticity compared to gases and liquids.

Explanation

Muscle is a type of tissue that contracts to produce movement.

The three main types of muscle tissues are skeletal, smooth, and cardiac.

Explanation

Explanation

Dmitri Mendeleev, a Russian chemist, formulated the Periodic Table in 1869, arranging chemical elements according to their atomic number (number of protons in the nucleus) and chemical properties.

He organized the elements in a logical and systematic order.

This making it easier to predict their behavior and relationships.

Explanation

• Sound travels fastest in diamond,
• With a speed of approximately 12,000 meters per second (m/s).
• Because sound travels fastest in stiff, dense materials

Additional information 
The speeds of sound in different materials:

• Air: 343 m/s
• Water: 1433 m/s
• Wood: 3300-3600 m/s
• Brick: 4176 m/s
• Steel: 6100 m/s
• Diamond: 12000 m/s