A phylogenetic tree is the representation of the evolutionary relationships among species. The fossil records are used as evidence to develop a phylogenetic tree. Thus, option A is correct.
<h3>What is a fossil record?</h3>
A fossil record is a depiction of the organisms that shared common ancestors and depicts the change in the structural and functional unit of the organism over many years of time.
They are used to illustrate the phylogenetic tree to show the morphological, structural, chemical, anatomical, etc variations in species that shared ancestry.
Therefore, option A. fossil records are used to show the common ancestry at the nodes.
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Answer: In most chemical reactions, bonds are both broken and made. Energy is absorbed when bonds are broken, and released when bonds are made. The sum total of the released (negative) energy and absorbed (positive) energy determines whether the overall reaction is exothermic or endothermic.
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Glycolysis is the first step in the respiration pathway. The amount of oxygen available after glycolysis determines whether the rest of the reaction is aerobic (Krebs Cycle and Electron Transport Chain) or anaerobic (Fermentation).
Were preserved remains of ancient organisms