This is because of a phenomenon is known as winter stratification in water bodies. In the winter season, the water at the top layer of water bodies will be ice cold (0°C) and are gradually frozen. But still, the bottom layers will have liquid water and maintain a temperature (4°C) which supports the life there. Thus, fishes and other aquatic animals are saved from the frozen top layer of water.

The color of light is determined by its wavelength. Different colors have different wavelengths. The wavelength of red colour is largest and violet colour has shortest wavelength.

Phosgene can form from chloroform, in presence of oxygen and UV light.

Bromine has lowest melting point in the following. It has melting point of -7.2℃.

A lymphocyte is one of the three sub types of white blood cell in a vertebrate’s immune system. Lymphocytes circulate in blood and lymph fluid is found in body tissues including the spleen, thymus, bone marrow, lymph nodes, tonsils, and liver. B-Lymphocytes and T-Lymphocytes are the two main types of lymphocytes.

The National Tourism Awards 2017-18 were recently presented by Vice President Venkaiah Naidu on the occasion of World Tourism Day (WTD-2019). In it, Andhra Pradesh has bagged 3 national tourism awards in different categories viz. ‘Best State for comprehensive development of tourism’, ‘Excellence in publishing in English’ and the ‘Best tourist-friendly Railway Station (Visakhapatnam).

The World Tourism Day (WTD) is observed every year on 27th of September to create awareness on the role of tourism among the international community and to demonstrate how it affects social, cultural, political and economic values worldwide. The 2019 theme is "Tourism and Jobs: A Better Future for All".

The West Bengal government has decided to set up a museum at the north Kolkata house of 19th century social reformer Ishwar Chandra Vidyasagar where he had spent the last few years of his life

The 4th edition of Indo-Kazakhstan joint military exercise “KAZIND – 2019” will be conducted at Pithoragarh from 2nd to 15th October 2019.

At Vigyan Bhawan in New Delhi, President Ram Nath Kovind inaugurated the 6th edition of ”India Water Week (IWW-2019)”, which is organised by Ministry of Jal Shakti with the theme of ”Water cooperation-coping with 21st-century challenge’ . Japan and European Union have been associated as partner countries for this mega event.