<span>The gas which was not prevalent in Earth’s atmosphere during the Hadean Eon is CO2. If you are going to see the composition of the Earth's atmosphere, Carbon Dioxide has the least percentage.
</span>This is because after the hydrogen and helium had escaped, Earth's Hadean atmosphere was left with methane, ammonia, water vapor, and small percentages of nitrogen and carbon dioxide.
See attached file for further information about the Earth's atmosphere during the Haedan Period.
<span>Segregation
For a trait to show or express itself in an individual it must have two types of the same allele (for example P and p) showing on the chromosomes. The showing of both alleles on an offspring's chromosomes means that both parents have the same trait and that is why there is a chance for an allele to become dominant in other words to express itself in the offspring. However if only one allele is transferred in the genes of the offspring that means that the trait that the allele is responsible for, will remain unexpressed.</span>
I'm sorry but can you be a bit more specific on these following observations?
The correct answer to this question is this one: they lacked oxygen. The earliest organisms were completely heterotrophic in nature because of the reason that they lacked oxygen. <span>A heterotroph is an organism that cannot fix carbon and uses organic carbon for growth. </span>
P waves do not move through liquid material