The Sangam was a confluence or conference of Tamil poets, which was probably held under the royal patronage of some chiefs or kings. According to the Tamil legends, there were three Sangams (Academy of Tamil poets) held in ancient South India popularly called Muchchangam. ‘Pathinenkilkanakku’ contains eighteen works about ethics and morals that are related to the third sangam. The most important among these works is Tirukkural authored by Thiruvalluvar, the Tamil great poet and philosopher. It is also considered as the Bible or the fifth Veda of Tamil literature.

Kautilya gave the final authority to the king in all matters of administration. Among the seven components of the state, the king is given the primary position. The Saptangas (seven limbs) of the state are King, Danda, Janapada, Amatya, Mitra, Durga, Kosa. Shatru (Enemy) - The 8th element added by Arthashastra.

The power to decide the date of an election to a State Legislative Assembly rests with the Election Commission of India. 

Right to freedom is enshrined in Articles 19-22. Article 21A mentions the “Right to elementary education”. Hence, Option B is correct.

World Day Against Child Labour is observed every year on June 12. This year's World Day Against Child Labour focuses on action taken for the 2021 International Year for the Elimination of Child Labour. The theme for World Day Against Child Labour 2021 is 'Act Now, End Child Labour'.

Africa ranks highest among regions both in the percentage of children in child labour — one-fifth — and the absolute number of children in child labour — 72 million. Asia and the Pacific rank second highest in both these measures — 7% of all children and 62 million in absolute terms are in child labour in this region. Hence, option B is correct.

• The group of organisms which occupy the same level in a food chain within an ecosystem is known as a trophic level.

• The concept is used as a representation of energy flow in an ecosystem.

• Energy flows through the trophic levels from producers to higher trophic level is unidirectional.

• The amount of energy decreases during the transfer from one tropic level to another in an ecosystem.

• Silver bromide (AgBr) is a soft, pale-yellow, water-insoluble salt known for its unusual sensitivity to light.
• This property has allowed silver halides to become the basis of modern photographic materials.
• Silver bromide is widely used in photographic films.

• The most common types of pencil are made of a mixture of clay and graphite and their darkness varies from light grey to black.
• Graphite archaically referred to as Plumbago, is a crystalline form of carbon, a semimetal, a native element mineral, and one of the allotropes of carbon. Graphite is the most stable form of carbon under standard conditions.