Answer: C

Explanation:

Superplasticizers, also known as high range water reducers, are chemical compounds that allow for the production of concrete with about 15% less water. Hence, statement 1 is correct.

They are effective water-reducing admixtures used in concrete to enhance workability and reduce water content while maintaining desired properties. Hence, statement 2 is correct.

They are commonly sulphonated melamine formaldehyde or sulphonated naphthalene formaldehyde condensates. They aid in the production of 'flowing' concrete, particularly beneficial for placing in inaccessible locations. Hence, statement 3 is incorrect.

They enable the production of high-strength concrete with normal workability and low water/cement ratios, reducing the heat of hydration in mass concrete structures. They are widely used in various construction projects including bridges, tunnels, dams and high-rise buildings to improve concrete performance and durability. Hence, statement 4 is correct.

Answer: A

Explanation:

The Black Sea, also known as the Euxine Sea is located at the southeastern tip of Europe, between Europe and Asia. It is a large inland sea that borders six countries including Georgia (East), Romania (West), Ukraine (North),  Russia (Northeast), Turkey (South) and Bulgaria (Southwest). Hence, statement 1 is correct.

The Black Sea is connected to the Mediterranean Sea by the Bosporus Strait, the Sea of Marmara and the Dardanelles Strait. It is also connected to the Sea of Azov by the Strait of Kerch. Hence, statement 2 is correct.

It receives freshwater inflows from the Danube, Dniepr and Dniestr rivers. It has numerous islands, with the biggest ones including Snake Island (Ukraine), Giresun Island (Turkey) and St. Ivan Island (Bulgaria). Hence, statement 3 is incorrect.

Answer: B

Explanation:

The report offers actions for countries to ensure food security, strengthen resilience against climate change and support vulnerable populations during the transition to net zero emissions in the agrifood system. Replacing a quarter of India's 8.8 million diesel irrigation pumps with solar pumps could reduce agrifood emissions by 11.5 million tonnes annually. This reduction surpasses the emissions prevented globally by electric vehicles and solar panels in 2020, as per a new World Bank report. The world's agrifood system emits around 16 gigatonnes of greenhouse gases (GHG) annually, constituting about one-third of global emissions, with projected growth. In India, 60% of agrifood emissions originate from the farm gate, with enteric fermentation being the largest contributor, mainly due to livestock sector inefficiencies. While India's rice production has low emission intensity globally, its considerable emissions (4%) result from being the second-largest rice producer. Hence, statements I and II both are correct but statement-II is not the correct explanation for statement-I. Hence, option (b) is correct.

Answer: D

Explanation:

Recently, new data has revealed that bird flu, specifically the H5N1 strain of highly pathogenic avian influenza (HPAI), has been spreading among cows in the United States for nearly five months. H5N1 is a highly pathogenic avian influenza (HPAI) virus strain that primarily affects birds but can also infect humans and other mammals. Hence, statement 1 is incorrect.

It has caused outbreaks in poultry and wild birds in many countries, resulting in significant economic losses and posing a potential threat to public health. The virus primarily spreads through contact with infected birds or their feces, saliva, or respiratory secretions. Human-to-human transmission is rare but possible, typically occurring in close contact with infected individuals. In humans, symptoms may include fever, cough, sore throat, muscle aches, pneumonia and acute respiratory distress syndrome (ARDS). Hence, statement 2 is also incorrect.

Answer: C

Explanation:

Recently, Scotland got its second leader in as many years, as parliament approved political veteran John Swinney to lead the country as First Minister. Scotland is a country/state in the United Kingdom, located in the northern third of Great Britain and 790 surrounding islands. Scotland shares its borders with the Atlantic Ocean to the north & west), the North Sea to the east & north-east) and the Irish Sea and England to the south. Edinburgh is the capital of Scotland. The highest point in Scotland is Ben Nevis, which is located near the town of Fort William in the Scottish Highlands. Hence, option (c) is correct.