Article: Dryer and rockier uplands and ridges are occupied by oak-chestnut type forests dominated by a variety of oaks (Quercus spp.), hickories (Carya spp.) and, in the past, by the American chestnut (Castanea dentata). The American chestnut was virtually eliminated as a canopy species by the introduced fungal chestnut blight (Cryphonectaria parasitica), but lives on as sapling-sized sprouts that originate from roots, which are not killed by the fungus. In present-day forest canopies chestnut has been largely replaced by oaks.

Question: What species of tree was pretty much eliminated?
Ans: The American chestnut


Article: In 1867, the university opened the first private nonsectarian law school west of the Mississippi River. By 1882, Washington University had expanded to numerous departments, which were housed in various buildings across St. Louis. Medical classes were first held at Washington University in 1891 after the St. Louis Medical College decided to affiliate with the University, establishing the School of Medicine. During the 1890s, Robert Sommers Brookings, the president of the Board of Trustees, undertook the tasks of reorganizing the university's finances, putting them onto a sound foundation, and buying land for a new campus.

Question: Who was Robert Somers Brookings?
Ans: the president of the Board of Trustees


Article: Due to extreme variation in elevation, great variation occurs in the climatic conditions of Himachal . The climate varies from hot and subhumid tropical in the southern tracts to, with more elevation, cold, alpine, and glacial in the northern and eastern mountain ranges. The state has areas like Dharamsala that receive very heavy rainfall, as well as those like Lahaul and Spiti that are cold and almost rainless. Broadly, Himachal experiences three seasons: summer, winter, and rainy season. Summer lasts from mid-April till the end of June and most parts become very hot (except in the alpine zone which experiences a mild summer) with the average temperature ranging from 28 to 32 °C (82 to 90 °F). Winter lasts from late November till mid March. Snowfall is common in alpine tracts (generally above 2,200 metres (7,218 ft) i.e. in the higher and trans-Himalayan region).

Question: What occurs in the climatic conditions of Himachal?
Ans: great variation


Article: Sleep involves great changes in brain activity. Until the 1950s it was generally believed that the brain essentially shuts off during sleep, but this is now known to be far from true; activity continues, but patterns become very different. There are two types of sleep: REM sleep (with dreaming) and NREM (non-REM, usually without dreaming) sleep, which repeat in slightly varying patterns throughout a sleep episode. Three broad types of distinct brain activity patterns can be measured: REM, light NREM and deep NREM. During deep NREM sleep, also called slow wave sleep, activity in the cortex takes the form of large synchronized waves, whereas in the waking state it is noisy and desynchronized. Levels of the neurotransmitters norepinephrine and serotonin drop during slow wave sleep, and fall almost to zero during REM sleep; levels of acetylcholine show the reverse pattern.

Question: During what stage of sleep do serotonin and norepinephrine levels drop?
Ans:
slow wave sleep