The replacement rate is the level at which a population remains stable.
<span>Replacement rate (level) is the fertility rate and represents the average number of children born per woman at which a population<span> exactly replaces itself from one generation to the next (without migration). More precisely, </span>it is the amount of fertility needed to keep the population the same, from generation to generation. As a result of the total <span>fertility rate,</span><span> there will be no increasing or decreasing of the population, it will be stable. </span></span>
Energy input is required as it is the activation energy needed for a reaction to start.
Isotopes are variants of a particular chemical element which differ in neutron number, although all isotopes of a given element have the same number of protons in each atom. The term isotope is formed from the Greek roots isos and topos, meaning "the same place"; thus, the meaning behind the name is that different isotopes of a single element occupy the same position on the periodic table.
Pain is more defined as a symptom
