The currency market, or foreign exchange market ("forex"), was created to facilitate the exchange of currency that becomes necessary as the result of foreign trade. That is, when an entity in one country sells something to an entity in another country, the seller earns that foreign currency. When China sells t-shirts to Walmart, for example, China earns US dollars. When Toyota wants to build a factory in the US, it needs dollars. It may get those from its local bank, which in turn will obtain them in the international currency market. This market exists to facilitate these types of exchanges.
A commodity market is a market that trades in primary economic sector rather manufactured products.  Soft commodities are agriculture products such as Wheat, coffee, sugar and cocoa. Hard commodities are mined products such as gold and oil. Future contracts are the oldest way of investing in commodities. Futures are secured by physical assets. Commodity market can includes physical trading in derivatives using spot prices, forwards, futures and options on futures. Collectively all these are called Derivatives.
For example: Tomatoes are cheap in July and will be expensive in January, you can’t buy them in July and take delivery in January, since they will spoil before you can take advantage of January’s high prices. The July price will reflect tomato supply and demand in July. The forward price for January will reflect the market’s expectations of supply and demand in January. July tomatoes are effectively a different commodity from January tomatoes.
Research is provided for informational purposes only, does not constitute advice or guidance, nor is it an endorsement or recommendation for any particular security or trading strategy. Research is provided by independent companies not affiliated with Fidelity. Please determine which security, product, or service is right for you based on your investment objectives, risk tolerance, and financial situation. Be sure to review your decisions periodically to make sure they are still consistent with your goals.

Options markets trade options contracts, with the smallest trading unit being one contract. Options contracts specify the trading parameters of the market, such as the type of option, the expiration or exercise date, the tick size, and the tick value. For example, the contract specifications for the ZG (Gold 100 Troy Ounce) options market are as follows:
In the case of perishable commodity, the cost of storage is higher than expected future price of a commodity (For ex: TradeINR prefer to sell tomatoes now rather than waiting for 3 more months to get a good price as a cost of storage of tomato is more than price they yield by storing the same). So in this case, the spot prices reflect current supply and demand, not future movements. There spot prices for perishables are more volatile.
With this strategy, the trader's risk can either be conservative or risky depending on their preference (which is a definite plus). For iron condors, the position of the trade is non-directional, which means the asset (like a stock) can either go up or down - so, there is profit potential for a fairly wide range. To use this kind of strategy, sell a put and buy another put at a lower strike price (essentially, a put spread), and combine it by buying a call and selling a call at a higher strike price (a call spread). These calls and puts are short.  

For strangles (long in this example), an investor will buy an "out of the money" call and an "out of the money" put simultaneously for the same expiry date for the same underlying asset. Investors who use this strategy are assuming the underlying asset (like a stock) will have a dramatic price movement but don't know in which direction. What makes a long strangle a somewhat safe trade is that the investor only needs the stock to move greater than the total premium paid, but it doesn't matter in which direction. 
When you buy an option, the risk is limited to the premium that you pay. Selling an option is the equivalent of acting as the insurance company. When you sell an option, all you can earn is the premium that you initially receive. The potential for losses is unlimited. The best hedge for an option is another option on the same asset as options act similarly over time.

The fee you are paying to buy the call option is called the premium (it's essentially the cost of buying the contract which will allow you to eventually buy the stock or security). In this sense, the premium of the call option is sort of like a down-payment like you would place on a house or car. When purchasing a call option, you agree with the seller on a strike price and are given the option to buy the security at a predetermined price (which doesn't change until the contract expires).