Questions

The Early Middle Ages have often been called the Dark Ages, and to some extent  they were truly dark. The people led a miserable life. Education was very uncommon. The helplessness of the comman man the arbitary rule of the king and the barons and the absence of national unity-all these conditions were common in Europe. The term 'Middle Ages' does not cover a uniform period for all the countries of the world.For Europe and the Westren World , the 'Middle Ages' are generally considered to be the period between AD 500 and AD 1500.

Arteries carry oxygenated blood away from the heart to the tissues, except for pulmonary arteries, which carry blood to the lungs for oxygenation (usually veins carry deoxygenated blood to the heart but the pulmonary veins carry oxygenated blood as well).

The law of conservation of energy is a law of science which states that energy can neither be created nor destroyed - only converted from one form of energy to another.

In 1842, Julius Robert Mayer discovered the Law of Conservation of Energy.

Phenol with a molecular formula [C₆H₅OH] is also called as Carbolic Acid. It is a white poisonous clear compound with sweet smell. It is used in making plastics, detergents and drugs.