QUES: Sometimes circumstances such as a good breeding season followed by a food source failure the following year lead to irruptions in which large numbers of a species move far beyond the normal range. Bohemian waxwings Bombycilla garrulus well show this unpredictable variation in annual numbers, with five major arrivals in Britain during the nineteenth century, but 18 between the years 1937 and 2000. Red crossbills Loxia curvirostra too are irruptive, with widespread invasions across England noted in 1251, 1593, 1757, and 1791.
For what reason would birds mor far beyond the normal range?

ANS: a good breeding season followed by a food source failure

QUES: The ancestors of modern bacteria were unicellular microorganisms that were the first forms of life to appear on Earth, about 4 billion years ago. For about 3 billion years, most organisms were microscopic, and bacteria and archaea were the dominant forms of life. In 2008, fossils of macroorganisms were discovered and named as the Francevillian biota. Although bacterial fossils exist, such as stromatolites, their lack of distinctive morphology prevents them from being used to examine the history of bacterial evolution, or to date the time of origin of a particular bacterial species. However, gene sequences can be used to reconstruct the bacterial phylogeny, and these studies indicate that bacteria diverged first from the archaeal/eukaryotic lineage. Bacteria were also involved in the second great evolutionary divergence, that of the archaea and eukaryotes. Here, eukaryotes resulted from the entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves possibly related to the Archaea. This involved the engulfment by proto-eukaryotic cells of alphaproteobacterial symbionts to form either mitochondria or hydrogenosomes, which are still found in all known Eukarya (sometimes in highly reduced form, e.g. in ancient "amitochondrial" protozoa). Later on, some eukaryotes that already contained mitochondria also engulfed cyanobacterial-like organisms. This led to the formation of chloroplasts in algae and plants. There are also some algae that originated from even later endosymbiotic events. Here, eukaryotes engulfed a eukaryotic algae that developed into a "second-generation" plastid. This is known as secondary endosymbiosis.
What are Stromatolites?

ANS: bacterial fossils

QUES: The Manchurian Strategic Offensive Operation began on 9 August 1945, with the Soviet invasion of the Japanese puppet state of Manchukuo and was the last campaign of the Second World War and the largest of the 1945 Soviet–Japanese War which resumed hostilities between the Soviet Union and the Empire of Japan after almost six years of peace. Soviet gains on the continent were Manchukuo, Mengjiang (Inner Mongolia) and northern Korea. The rapid defeat of Japan's Kwantung Army has been argued to be a significant factor in the Japanese surrender and the end of World War II, as Japan realized the Soviets were willing and able to take the cost of invasion of its Home Islands, after their rapid conquest of Manchuria and Invasion of South Sakhalin island.
Who gained Manchukuo, Mengjiang, and northern Korea after the Manchurian Strategic Offensive Campaign?

ANS: Soviet Union

QUES: In Eastern Catalan (except Majorcan), unstressed vowels reduce to three: /a e ɛ/ > [ə]; /o ɔ u/ > [u]; /i/ remains distinct. There are a few instances of unreduced [e], [o] in some words. Alguerese has lowered [ə] to [a].
Where do unstressed vowels reduce to three?

ANS:
Eastern Catalan