Article: Occupancy sensors to allow operation for whenever someone is within the area being scanned can control lighting. When motion can no longer be detected, the lights shut off. Passive infrared sensors react to changes in heat, such as the pattern created by a moving person. The control must have an unobstructed view of the building area being scanned. Doors, partitions, stairways, etc. will block motion detection and reduce its effectiveness. The best applications for passive infrared occupancy sensors are open spaces with a clear view of the area being scanned. Ultrasonic sensors transmit sound above the range of human hearing and monitor the time it takes for the sound waves to return. A break in the pattern caused by any motion in the area triggers the control. Ultrasonic sensors can see around obstructions and are best for areas with cabinets and shelving, restrooms, and open areas requiring 360-degree coverage. Some occupancy sensors utilize both passive infrared and ultrasonic technology, but are usually more expensive. They can be used to control one lamp, one fixture or many fixtures.

Question: What does a passive infrared sensor react to? 
Ans: changes in heat


Article: The discipline of plant ecology was pioneered in the late 19th century by botanists such as Eugenius Warming, who produced the hypothesis that plants form communities, and his mentor and successor Christen C. Raunkiær whose system for describing plant life forms is still in use today. The concept that the composition of plant communities such as temperate broadleaf forest changes by a process of ecological succession was developed by Henry Chandler Cowles, Arthur Tansley and Frederic Clements. Clements is credited with the idea of climax vegetation as the most complex vegetation that an environment can support and Tansley introduced the concept of ecosystems to biology. Building on the extensive earlier work of Alphonse de Candolle, Nikolai Vavilov (1887–1943) produced accounts of the biogeography, centres of origin, and evolutionary history of economic plants.

Question: What did Warming believe that plants can do?
Ans: form communities


Article: Federalism refers to the mixed or compound mode of government, combining a general government (the central or 'federal' government) with regional governments (provincial, state, Land, cantonal, territorial or other sub-unit governments) in a single political system. Its distinctive feature, exemplified in the founding example of modern federalism of the United States of America under the Constitution of 1789, is a relationship of parity between the two levels of government established. It can thus be defined as a form of government in which there is a division of powers between two levels of government of equal status.

Question: What document exemplified modern federalist government?
Ans: Constitution of 1789


Article: For nearly 2000 years, Sanskrit was the language of a cultural order that exerted influence across South Asia, Inner Asia, Southeast Asia, and to a certain extent East Asia. A significant form of post-Vedic Sanskrit is found in the Sanskrit of Indian epic poetry—the Ramayana and Mahabharata. The deviations from Pāṇini in the epics are generally considered to be on account of interference from Prakrits, or innovations, and not because they are pre-Paninian. Traditional Sanskrit scholars call such deviations ārṣa (आर्ष), meaning 'of the ṛṣis', the traditional title for the ancient authors. In some contexts, there are also more "prakritisms" (borrowings from common speech) than in Classical Sanskrit proper. Buddhist Hybrid Sanskrit is a literary language heavily influenced by the Middle Indo-Aryan languages, based on early Buddhist Prakrit texts which subsequently assimilated to the Classical Sanskrit standard in varying degrees.

Question: What are two examples of epic poetry written in Sanskrit?
Ans:
the Ramayana and Mahabharata