Questions

A simple rule concerning water and electrolyte regulation is water passively follows salt.

Mercury was the remedy of choice for syphilis in Protestant Europe. Until the early 20th century, the primary treatment for syphilis was mercury, in the form of calomel, ointments, steam baths, pills, and other concoctions.

Mercury was already being used in Western Europe to treat skin diseases.

Hedging is a tool to minimize the risks. It is thus like an 'insurance' where one pays a premium but gets an assured amount in case of some uncertain event to the extent of the loss actually suffered on an equally opposite position for which the hedge was done. Thus, hedger is different from arbitrageur and speculators, as the intention here is not to maximize the profit but to minimize the loss.

E.g. In Capital Markets, suppose an investor has an equity portfolio of Rs. 2 lacs and the portfolio consists of all the major stocks of NIFTY. He thinks the market will improve in the long run but might go on a downside in the shortrun. NIFTY today stands at 4300. To minimize the risk of downfall, he enters into an option contract by buying NIFTY-PUT of strike 4300 at a premium of, say, Rs. 100. Thus, the actual amount paid is Rs. 5,000(lot size of NIFTY is 50). Also, the number of NIFTY-PUTs to be bought will vary on the beta of the portfolio so as to completely hedge the positon. 

The ancient goal of astrology was to predict human events.

The data bus is Bi-directional because the same bus is used for transfer of data between Micro Processor and momory of input / output devices in both the direction.