Scientists will look for evidence like similar body or skeleton structures, internal similarities or maybe sometimes the whole heirarchy to confirm that two speices are closely related to each other.
For example ; in birds, scientists will look for type of feathers, body structure, beaks to confirm the similarity of two birds.
<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.
D. Photosynthesis only takes place in the light, while cellular respiration takes place in the light and dark.