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.
you could chose to describe the first graph as any of the following phrases:
‘curved graph’
‘intercept on y-axis’
‘as x increases, y increases’,
‘y increases slowly at first, then more rapidly, then slows down again’ and ‘reaches a maximum level’.
you can chose to describe the second graph as any of the following phrases:
'gradually increases, then rapidly increases in a short period of time"
