George Strait has the most #1 hits at 57 and counting. Nobody else comes close. Conway Twitty actually had the most until 2006 with 55 #1 hits. The Beatles are the musical act with the most songs to reach No. 1 on the Billboard singles chart. Mariah Carey has 18 such #1 hits and Elvis Presley 17.
Primary succession begins on rock formations, such as volcanoes or mountains, or in a place with no organisms or soil. This creates conditions nearer optimum for vascular plant growth; pedogenesis or the formation of soil is the most important process.
Primary ecological succession is the changing sequence of communities starting with the first biological occupation of a place where there were no living organisms previously. For example, the colonization and the following succession of communities on a bare rock is a case of primary ecological succession. Secondary ecological succession is the changing sequence of communities starting with the substitution of a community by a new one in a given place.