askscience

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How stable is the human oral microbiome against disruptions like mouthwash? If I use alcohol mouthwash will my mouth microbiome be back to the same amount and species ratio by my next meal? Several meals? Or never quite the same again?	4820
Is there a latency period for human vitamin D production upon UVB exposure, or are skin cells synthesizing vitamin D as soon as exposed? Would we get the same amount of vitamin D from 60 ten-second periods of sunlight as from a single 10 minute period of sunlight?	546
Is a railgun chamber sealed up tight like a traditional firearm? If it is, does negative atmospheric pressure develop behind the projectile as it moves down the barrel? If it does, does it represent a problem or velocity limitation that has to be dealt with somehow? If so, how?	40
Do we know how animals with ridiculously long necks and relatively compact bodies like Tanystropheus and the Plesiosaurians avoid the snorkel problem? Were their bodies just 80% lung?	28
How do birds that spend long periods of time cruising at high altitude, especially bare-headed vultures and the like, protect their skin and vision from UV damage?	21
Do people with above-average visual acuity benefit from low-magnification optical aids (binoculars & scopes in the 2x range or lower) the same way average or poorer-sighted people do?	15
Why do domestic horses and some donkey breeds have floppy manes, while seemingly every wild equid has or had an upright mane (e.g. Przewalski's horse, all the wild asses, zebras and the extinct horses in prehistoric cave art)?	10
If/when carbon capture becomes a thing, how distributed would carbon capture points have to be? Would they need to be right next to carbon production points in order to not take 100s of years to affect the global system?	9
Artists picking color schemes talk about the psychology of certain colors a lot (red = rage/passion, green = nature/health, yellow=activity/sportiness, etc.) and often discuss them as cultural universals. Are they?	9
Do male sharks & their relatives exhibit "clasperedness"? i.e. do individuals prefer to use on or another of their two claspers in mating more often than others & does it vary similarly to right & left handedness in humans?	2

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