Insurance is the sharing of risks. Nearly everyone is exposed to risk of some sort. The house owner, for example, knows that his property can be damaged by fire; the ship-owner knows that his ships may be lost at sea; the breadwinner knows that he may die at an early age and leave his family poorer. On the other hand, not every house is damaged by fire nor every ship is lost at sea. If these persons each put a small sum into a pool, there will be enough to meet the needs of the few who do suffer losses. In other words, the losses of the few are met from the contributions of the many. This is the basis of insurance. Those who pay the contribution are known as insured and those who administer the pool of contributions as insurers.

     By “the pool of contributions” the writer means （） .