1 Although any individual may develop a case of pinworms, the infection occurs most frequently in school children between 5 to 10 years of age.  Pinworm infections occur in all socioeconomic groups; however, human-to-human spread is favored by close, crowded living conditions. Spread among family members is common.
Before they start collecting, stamp collectors try to identify the types of stamps. These will help them segregate and sort stamps according to their classification. On its basic concept, there are three main classifications of stamps â special, commemorative, and definitive.
Quick Answer. According to Stamps.com, a First-Class stamp gives a postal customer a cost-effective option to mail items using the United States Postal Service, also known as USPS. Postcards, letters, large envelopes and packages under 13 ounces can be mailed using First-Class postage. Continue Reading.