D because to help preserve environment everyone has to work together
Think about it. Caves are dark, with little to no light. If there's no light, why would you need to see? There are far more important senses than sight in cases like these. Senses such as smell, hearing, and touch.
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Answer:
The characteristic features of the phylum Chordata are a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a tailgut.
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Laurentia<span> (</span>North American Craton<span>) is a large continental </span>craton<span> that forms the ancient geological core of the </span>North American<span> continent. Many times in its past, Laurentia has been a separate </span>continent<span> as it is now in the form of North America, although originally it also included the cratonic areas of </span>Greenland<span> and also the northwestern part of </span>Scotland, known as theHebridean Terrane<span>. During other times in its past, Laurentia has been part of larger continents and </span>supercontinents<span> and itself consists of many smaller </span>terranes<span> assembled on a network of Early </span>Proterozoic orogenic<span> belts. Small </span>microcontinents<span> and oceanic islands collided with and sutured onto the ever-growing Laurentia, and together formed the stable </span>Precambriancraton seen today.
Milankovitch cycle, its named for the man who theorized it
