The answer is transcription and translation
Because it allows only certain substances to permeate. If it was totally permeable that would be good enough to having no barrier as it would let everything though. Totally impermeable means that nothing would get through.
Answer: Amylose
Explanation: Which complex carbohydrate contains only a-1,4-glycosidic linkages? Amylose (Amylose is formed from a-1,4-glycosidic linkages of glucose.)
Well, there are many birds that could fit this description, such as frigatebirds, flamingos, ducks, emperor penguins, parrots, albatrosses, blue manakins, grebes, etc.
But I'm assuming the correct answer should be peacocks - they are birds which are famous for performing a ritualized mating dance, although any of the options I listed could also be correct.
Answer:
Scientists show evidence that nitrogen acquired during Earth's formation came from both the inner and outer regions of the protoplanetary disk. Nitrogen is a volatile element that, like carbon, hydrogen and oxygen. Nitrogen makes up 78 per cent of the air we breathe, and it's thought that most of it was initially trapped in the chunks of primordial rubble that formed the Earth. When they smashed together, they coalesced and their nitrogen content has been seeping out along the molten cracks in the planet's crust ever since.