A covalent bond is a chemical bond which involves the sharing of atoms.
Mainly because it was extremely hot at the beginning of Earth's time.
My Answer: Vestigial organs
Why?: " Vestigial organs are physical structures that were fully developed
and functional in an ancestral group of organisms but are reduced
and unused in the later species."
Hope I helped! :D
A dichotomous key is defined as a biological tool for identifying unknown organisms to a particular taxonomic level. It is constructed with many levels and series of couplets.
So, by observing the given dichotomous key, it is concluded that the correct answer is Option A- Organism X and Z have at least one observable trait in common in this dichotomous key.
