Each new dna double helix consists of one old dna strand and one new dna strand, daughter dna
Look on the internet please
The correct asnwer to your question - why would a group of antelopes leave the herd for search of a better grassland is an example of emigration - B.
These antelopes would emigrate to a certain grassland and be immigrants in that grassland. This has to be distinguished.
When a top predator is removed from an ecosystem, a series knock-on effects are felt throughout all the levels in a food web, as each level is regulated by the one above it. This is known as a trophic cascade. The results of these trophic cascades can lead to an ecosystem being completely transformed. The impacts trickle down through each level, upsetting the ecological balance by altering numbers of different animal species, until the effects are finally felt by the vegetation.