Which gas is removed from the atmosphere during photosynthesis?

1) homologous features:

these are the features or structures that have similar structure in several different organisms but function in a unique way in all of them. these structures indicate anatomical similarities as well as same ancestry of different organisms. for example, the forelimb of birds, humans, dogs and whales, perform different function in all these organisms. but when we analyse the layout of bones or layout of arrangement, we find that it is very similar across all of them. this indicates that, the ancestor of all these organisms was was, but with the passage of time when organism dispersed, and environmental conditions changed, it was evolved into different organisms as per favorable conditions.

2) molecular biology:

as we know that all living organisms are a compilation of billions and trillions of unique biological molecules, that group in unique fashion to constitute whole organism. interestingly, some biological molecules and the process of their formation can provide sound evidences of evolution. for example, dna,   sequence of nucleotide in dna, amino acids, process of transcription, translation etc.

the study of evolution through molecular uniformity has led to the foundation of a novel branch of evolution called phylogenetics. the sequence of nucleotides in dna is used to find the best possible ancestor of any organism. for example, phylogenetic analysis has found that the origin of eukaryotes is from prokaryotes over the period of time.

3) fossil records:

fossils are the preserved remains of previously living organisms or their traces, dating from the distant past. this don't means that fossils represent complete skeleton of an organism, because many organisms don't even fossilize and those who fossilize don't have complete remains.nonetheless, the fossils that humans have collected offer unique insights into evolution over long timescales. for example, study of horse fossils has enabled the scientists to reconstruct a large, branching "family tree" for horses and their now-extinct relatives.

you answered yourself there buster.

examples of products that contain carrageenan are dog food, chocolate, toothpaste and baby food. alginate comes from brown algae and is used to make water-based products thicker or creamier. ranch dressing, heartburn relief medicine and hand creams all can contain alginate.

*carrageenans or carrageenins are a family of linear sulfated polysaccharides that are extracted from red edible seaweeds. they are widely used in the food industry, for their gelling, thickening, and stabilizing properties. (wiki)

fossil number 10 was probably the first of the four to live on earth.