<span>The correct word to fill the gap is "gene flow". Moreover, gene flow is the transfer of alleles or genes from one population to another. It can happen due to migration or immigration. When that happens a new genetic variants to the established gene pool of a particular species or population is created.</span>
<span>In the given scenario, a certain mouse with curled whisker mates with other mice in the community to where she migrated to. Her passed the gene for curled whiskers to here offspring. The scenario is an example of gene flow which basically means the passing of genes to the offspring. </span>
Energy decreases as it moves up trophic levels because energy is lost as metabolic heat when the organisms from one trophic level are consumed by organisms from the next level.
