Sound is a mechanical longitudinal wave. It is mechanical because it creates different pressure regions during its transmission. It is called longitudinal because the particles of medium through which it travels vibrate parallel to the direction of propagation.

Atom is known as the fundamental unit of elements, which has an independent existence in a compound or the mixture. They are extremely small; typical sizes are around 100 picometers. Every atom is composed of a nucleus and one or more electrons bound to the nucleus.

Godavari river is known as Dakshin Ganga which means Ganga of the South India. It is the second longest river of India after Ganga. It forms the largest peninsular river system as it is the largest river of South India. It rises in the Nasik district of Maharashtra and falls into Bay of Bengal.

Former Foreign Minister Moctar Ouane was elected as Mali's new prime minister by the West African country's interim government on 29^th September 2020. He has also served as Mali’s ambassador to the UN from 1995-2002, and also as foreign minister from 2004-2009 during Amadou Toumani Toure’s presidency.

INDRA 2020 - bilateral naval exercise between India and Russia in Andaman Sea, close to strategic Strait of Malacca, Bay of Bengal.

Nazhat Shameem Khan is appointed as president of UN Human Rights Council for 2021 in an unprecedented secret ballot after a diplomatic stand-off blocked the usual consensus decision. Nazhat Shameem Khan served as the council’s vice president in 2020 and is considered a rights champion.

The 42^nd Constitutional Amendment Act (1976) included 10 Fundamental Duties.

• They are included in Part IV A under Article 51 A

• Non-justiciable in nature

• Only for Indian citizens

• 11^th duty was incorporated by 86^th Amendment Act, 2002

The phylum name Platyhelminthes literally means "flatworms." Members of this phylum are soft, thin-bodied, leaf or ribbonlike worms, including the familiar planaria of ponds and streams, as well as the flukes and tapeworms parasitic in human and other animal bodies. Some defining characteristics of the phylum are that flatworms are acoelomate (they have no body cavity), triploblastic (the body has three tissue layers), and bilaterally symmetric (they have symmetric right and left sides and usually a definite head), and they have organ systems, including an excretory, digestive, reproductive, and nervous system, but no respiratory system.

* The tribe “Zulus” is found in Southern part of Africa. They are considered warriors.

* The Zulu are the largest South African ethnic group, with an estimated 10–11 million people living mainly in the province of KwaZulu-Natal.

* The language of the Zulu people is "isiZulu".

* The Zulu people celebrate an annual event that was established in 1984 called the Umhlanga or Reed Dance.

* Small numbers also live in Zimbabwe, Zambia and Mozambique.

* The Zulu Kingdom played a major role in South African history during the 19th and 20th centuries.

• A part of the total deposit of Commercial Banks which is held as a reserve as mandated by the Reserve Bank of India is known as Cash Reserve Ratio.

• This amount is held in the form of cash or cash equivalent which is stored with the Commercial Bank or deposited with the RBI.

• CRR helps in regulating the money supply and the level of inflation in India.

• It also ensures that the banks do not run out of money in difficult situations.

• Increase in Cash Reserve Ratio reduces the money supply in an economy while decrease in Cash Reserve Ratio increases the money supply.

• Reduction in Bank Rate might reduce or nullify the effect of increase in Cash Reserve Ratio.