Based on the information present in the given passage, you need to write a correct answer to the given question. A correct answer is one that correctly and completely answers the question. Do not write answers that address the question partially or incorrectly. The correct answer must be contained in the given paragraph.

Paragraph- Sent 1: You couldnt survive without your skin.
Sent 2: It has many important functions.
Sent 3: The main function of the skin is controlling what enters and leaves the body.
Sent 4: It prevents the loss of too much water from the body.
Sent 5: It also prevents bacteria and other microorganisms from entering the body.
Sent 6: The skin helps maintain a constant body temperature.
Sent 7: It keeps the body cool in two ways.
Sent 8: Sweat from sweat glands in the skin evaporates to cool the body.
Sent 9: Blood vessels in the skin dilate, or widen.
Sent 10: This action increases blood flow to the body surface.
Sent 11: This allows more heat to reach the surface.
Sent 12: The heat is then able to radiate off the body.
Sent 13: The opposite happens to retain body heat.
Sent 14: Blood vessels in the skin constrict, or narrow.
Sent 15: This decreases blood flow to the body surface.
Sent 16: This reduces the amount of heat that reaches the surface.
Sent 17: When this happens, less heat can be lost to the air. 
Question: What is different when something constricts as compared to when it dilates?.
Diameter.

Paragraph- Sent 1: Hundreds of thousands of years before China was to become the world's longest-running civilization, the prologue was enacted by means of the flicker of a carefully tended fire.
Sent 2: Peking Man, a forebear of Homo sapiens, achieved a mastery of fire.
Sent 3: We might call it the first Chinese invention.
Sent 4: Not that he devised flint and steel, matches, or any other way of creating fire.
Sent 5: Peking Man simply learned how to capture flame, perhaps from a forest fire, and keep it alight.
Sent 6: He thus enjoyed two revolutionary luxuries: light and heat.
Sent 7: Technologically and sociologically, it was a phenomenal breakthrough: with fire, communities could live year 'round in one cave, in which cooking and even smelting could be pursued.
Sent 8: And so, by 600,000 b.c., about 50 km (31 miles) southwest of present-day Beijing, the ancestors of mankind were ready to settle down.
Sent 9: Several hundred thousand years later, when Marco Polo reached the capital of China, he was astonished by a further development in fire technology.
Sent 10: The Chinese, he announced, used black stones dug out of mountains as fuel.
Sent 11: Europeans did not yet have a word for "coal," nor had they discovered a use for it.
Sent 12: The First Dynasty The confluence of mythology and history in China took place around 4,000 years ago during what is referred to as the Xia (Hsia) Dynasty.
Sent 13: This was still the Stone Age, but the people are thought to have made silk from thread produced by the worms they cultivated on the leaves of their mulberry trees.
Sent 14: And written language (which evolved as early as 4,500 to 5,000 years ago) was already in use, originally by oracles and then by official scribes — China's first scholars.
Sent 15: During the second of the quasi-legendary dynasties, the Shang (from about the 16th to 11th centuries b.c.), the Chinese developed an interest in art.
Sent 16: Careful geometric designs as well as dragon and bird motifs adorned bowls and implements.
Sent 17: And with the arrival of the Bronze Age, the Chinese created bronze vessels of such beauty and originality that, until modern times, archaeologists refused to believe they were cast 3,000 years ago.
Sent 18: The Shang Dynasty gave rise to the concept of one Chinese nation under one government. 
Question: This famous explorer , after reaching China's capital city reported that the Chinese used what color rocks to make fire?.
Marco Polo was amazed they used black rocks for fuel.

Paragraph- Sent 1: Independence with Partition: The British began to see India's independence as inevitable; however, only a few seemed to understand the vital role of the religious groups.
Sent 2: Britain prepared a parliamentary democracy with majority rule, but the majority were Hindus — and Hindus, Muslims, and Sikhs had been killing each other in war for many centuries.
Sent 3: Nehru's Congress Party, largely Hindu with a socialist leadership, wanted a parliamentary democracy.
Sent 4: As counterweight, British legislation reserved parliamentary seats for religious minorities, but the Punjab and Bengal had such a complicated mixture of Hindus, Muslims, and Sikhs that it was not possible to avoid fights over how separate constituencies were to be formed.
Sent 5: The seeds of future trouble were sown.
Sent 6: The legislation on reserving seats gave the Muslims the basis for an alternative to an India in which they were only a quarter of the population: Partition.
Sent 7: In 1930, the poet Muhammad Iqbal proposed a separate Muslim homeland in the northwest of India.
Sent 8: A small group of Indian Muslims at Cambridge came up with the name Pakistan, using the initials of the Punjab, Afghania (N.W. Frontier Province), Kashmir, and Sind (at the same time producing the word pak, meaning "pure"), and adding "stan," the Persian suffix for the word "country.
Sent 9: " The Muslim campaign for Partition was led by London-trained Bombay lawyer, Muhammad Ali Jinnah.
Sent 10: Meanwhile, Gandhi vehemently opposed any dismemberment of the country, and tried to keep people united by fasting to uphold the spirit of love, and by focussing on the common adversary: the British.
Sent 11: Advocating civil disobedience, he led his famous Salt March to the sea, to scoop up salt and circumvent the hated British salt tax.
Sent 12: This put more than 60,000 in jail.
Sent 13: Against this militancy, World War II did not elicit the solidarity of the first.
Sent 14: Indians courageously fought alongside the British troops, in Burma, the Middle East, and Europe, but Gandhi saw the British as a provocation for Japanese invasion and was jailed yet again, for launching a "Quit India" campaign in the year 1942.
Sent 15: Some anti-British extremists saw the Japanese as an Asian liberator.
Sent 16: Winston Churchill didn't want any Indian independence and so it was probably as well for India that he was defeated by Attlee's Labor Party in 1945.
Sent 17: With riots growing ever more bloody in Bengal, Bihar, and the Punjab, India's last viceroy, Lord Mountbatten, kept a mandate to make the British departure as quick and as smooth as possible.
Sent 18: Quick it was — six months after his arrival — but not smooth. 
Question: What march was held by Gandhi to refocus his country's citizens on the common adversary-the British?.

Salt March to the sea.

