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 answer is through the placenta. The placenta is formed in the uterus of the pregnant woman. Its role is in the nourishment of the fetus. The placenta provides the fetus with nutrients and removes waste. The umbilical cord connects the placenta to the fetus and it serves as the transporting passageway.
You need to be a bit more specific!!