The interaction is seemingly neutral for one of the organisms. For example, a barnacle attached to a whale can travel thousands of miles collecting and filtering food from the moving water. The whale doesn't seem to be affected by the little hitchhikers.
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>
Eight of them. If the last xero was not significant it should not be there
B. By mutating their DNA in response to environmental conditions to gain beneficial traits.
