how were the first island group formed?
The sea levels rose at the start of the Holocene.
Neptune Islands
The Neptune Islands were formed between 10800 and 12000 years ago when sea levels rose at the start of the Holocene.

how can you tell if a great white shark is a male or female n great white sharks, sexual dimorphism is present, and females are generally larger than males. where are these sharks found? United States (Northeast and California), South Africa, Japan, Oceania, Chile, and the Mediterranean including Sea of Marmara and Bosphorus. what do they feed on? Fish (e.g. tuna, rays, other sharks), cetaceans (i.e., dolphins, porpoises, whales), pinnipeds (e.g. seals, fur seals, and sea lions), etc. how are these sharks used to attract tourists? Cage diving is most common at sites where great whites are frequent. where is this activity famous? The coast of South Africa, the Neptune Islands in South Australia, and Guadalupe Island in Baja California.
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Neptune Islands [SEP] Formation, geology and oceanography
Water depths of are reached within a distance of from the Northern group and within 1.5 km to from the Southern group.