<span>Large changes in allele frequencies can occur in a short time.
I'm taking the test now and that's what I know.</span>
Answer:
SA node
Explanation:
The SA node (called the pacemaker of the heart) sends out an electrical impulse. The upper heart chambers (atria) contract. The AV node sends an impulse into the ventricles. The lower heart chambers (ventricles) contract or pump.
He begins to grow other plants that are planted and need in forests and maybe grow more trees!
Population density is the characteristics of a population increase with plentiful of resources. Population density is the measurement of every person in the population per unit area or unit volume. It is applied to a living organism and most of the time on humans. It is also the number of people living in each unit of area such as a square mile.
