Fossils only form if certain qualifications are met, and some organisms cannot meet them, so they just cease to exist, not a single sign of them. This could happen if they were organisms that decayed completely. Fossilization can include freezing, drying, and encasement, usually in tar or resin.
Part A:
<span>If early conditions of primeval earth had ammonia, methane, hydrogen in its atmosphere, then it is possible that amino acids such as glycine, α-alanine, and β-alanine may have been spontaneously formed from chemical reactions spurred by energy from lightning.</span>
<span>Their hypothesis was that the early conditions of primeval earth favored the spontaneous formation of organic molecules, from inorganic precursors, that may have been the origin of life. This theory is called abiogenesis. </span>
Part B:
<span>Miller Urey put methane, ammonia, hydrogen gases in a glass flask and a pool of water at the bottom of the glass flask. The flask was heated moderately to simulate the hot conditions then. Sparks were also occasionally induced in the flask to mimic lighting. The flask was then cooled slowly to simulate cooling of earth over time.After one day, they found the presence of some amino acids (glycine, α-alanine and β-alanine) was discovered in the water in the flask</span>
Answer:
Dark Energy, Dark Matter
In the early 1990s, one thing was fairly certain about the expansion of the universe. It might have enough energy density to stop its expansion and recollapse, it might have so little energy density that it would never stop expanding, but gravity was certain to slow the expansion as time went on. Granted, the slowing had not been observed, but, theoretically, the universe had to slow. The universe is full of matter and the attractive force of gravity pulls all matter together. Then came 1998 and the Hubble Space Telescope (HST) observations of very distant supernovae that showed that, a long time ago, the universe was actually expanding more slowly than it is today. So the expansion of the universe has not been slowing due to gravity, as everyone thought, it has been accelerating. No one expected this, no one knew how to explain it. But something was causing it.
Eventually theorists came up with three sorts of explanations. Maybe it was a result of a long-discarded version of Einstein's theory of gravity, one that contained what was called a "cosmological constant." Maybe there was some strange kind of energy-fluid that filled space. Maybe there is something wrong with Einstein's theory of gravity and a new theory could include some kind of field that creates this cosmic acceleration. Theorists still don't know what the correct explanation is, but they have given the solution a name. It is called dark energy.
