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In 1969, a specific binding protein for vitamin D called the vitamin D receptor was identified. [223] Shortly thereafter, the conversion of vitamin D to calcifediol and then to calcitriol, the biologically active form, was confirmed. [224] The photosynthesis of vitamin D 3 in skin via previtamin D 3 and its subsequent metabolism was described ...
It is a theory of biological evolution that seeks to explain aspects of organisms' anatomy and behavior by reference to the way that their life histories—including their reproductive development and behaviors, post-reproductive behaviors, and lifespan (length of time alive)—have been shaped by natural selection.
The earliest evidence for life on Earth includes: 3.8 billion-year-old biogenic hematite in a banded iron formation of the Nuvvuagittuq Greenstone Belt in Canada; [30] graphite in 3.7 billion-year-old metasedimentary rocks in western Greenland; [31] and microbial mat fossils in 3.48 billion-year-old sandstone in Western Australia.
The theory of a universal common ancestry of life is widely accepted. In 2010, based on "the vast array of molecular sequences now available from all domains of life," [ 70 ] D. L. Theobald published a " formal test " of universal common ancestry (UCA).
This forms an important part of the evidence on which evolutionary theory rests, demonstrates that evolution does occur, and illustrates the processes that created Earth's biodiversity. It supports the modern evolutionary synthesis—the current scientific theory that explains how and why life changes
There are two sources of vitamin D: Vitamin D2 comes from fortified foods and mushrooms, while vitamin D3 is produced in the skin when exposed to sunlight (which is why it’s often known as the ...
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Mapping of several bone diseases onto levels of vitamin D (calcidiol) in the blood [6] Normal bone vs. osteoporosis. Vitamin D deficiency is typically diagnosed by measuring the concentration of the 25-hydroxyvitamin D in the blood, which is the most accurate measure of stores of vitamin D in the body.