Questions

The carbon, oxygen, hydrogen and nitrogen are the key elements in aminoacids as all aminoacids contain amine (NH2) and carboxyl (COOH) as functional groups and R group for every specific aminoacid.

The femur is the longest bone in the human body. It is also called as thigh bone. Stapes in the shortest bone in the body that is present in the middle ear.

Feudalism was the dominant social system in medieval Europe, in which the nobility held lands from the Crown in exchange for military service, and vassals were in turn tenants of the nobles, while the peasants were obliged to live on their lord's land and give him homage, labour, and a share of the produce, notionally in exchange for military protection.

Feudalism was a combination of legal and military customs in medieval Europe that flourished between the 9th and 14th centuries.Feudalism was based on the division of land by the king to nobles and vassals in return for their military service under the Feudal Levy.

The land was the main source of the economy and was dependent on the peasants who worked on the land.

The reasons for the decline of Feudalism during the Medieval period of the Middle Ages included:

• The Crusades and travel during the Middle Ages opened new trade options to England
  England started to move from land-based economy to a money-based economy.

• The Black Death - this reduced the population of England by one third. Labour became a valuable commodity.

• The Peasants Revolt - Peasants realized their worth and demanded changes. Charters were granted but ignored by nobles.

• More trade saw the growth of more towns.

• Peasants moved away from the country into towns they were eventually allowed to buy their freedom.

• The land was rented and the rights of lords over labor decreased.
  
  


• Armed men were paid a wage and Medieval warfare was financed by taxes and loans
  Nobles became weaker - the Kings took back their lands and power.

• A centralized government was established.

Alkanes are saturated hydrocarbons. Saturated means that the hydrocarbon has only single bonds and that the hydrocarbon contains the maximum number of hydrogen atoms for each carbon atom.