Answer:
common ancestor.
Explanation:
when two groups of organism are related it means they share a common ancestry but may be they are not a direct parent but can relate to there far back generation.
Evidence from fossil's records are used to study that today how much organisms have changed themselves according to the environmental changes on earth. DNA and genetic codes mainly shows the shared common ancestry.
The first event or first thing they do, because the first thing they do is exercise for 2 hours everyday to keep their muscle and bone strength.
How the universe was created:)
