Why is the pulmonary circulation reduced in the human fetus? Pulmonary circulation is reduced in the human fetus because the baby gets its oxygen from its mother and does not breath on its own.
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They lie flat when we are warm, and rise when we are cold. The hairs trap a layer of air above the skin, which helps to insulate the skin against heat loss. For example, if we become too cold, the hair erector muscles contract.
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these are called Metalloids. They touch in between the metals and non-metals
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Sonic Hedgehog.
Explanation:
Sonic hedgehog is a secreted protein that in humans is encoded by the SHH gene. It is the best studied ligand of the hedgehog signaling pathway, others being desert hedgehog (DHH) and Indian hedgehog (IHH). It plays a key role in the development of animals, from insects to mammals. In vertebrates, it is involved in organogenesis, including the growth of digits on limbs and the organization of the brain.
Sonic hedgehog has also been shown to act as an axonal guidance cue. It has been demonstrated that SHH attracts commissural axons at the ventral midline of the developing spinal cord. Specifically, SHH attracts retinal ganglion cell (RGC) axons at low concentrations and repels them at higher concentrations