Chemical (mutagens)
usually either mimic the structure of nucleotides and are inserted in DNA or either cause
chemical changes (such as alkylation) in nucleotides hence causing mismatching during replication.
Radiation, on the other hand, (due to its high energy) causes double-strand breaks in DNA causing an
increased likelihood of mutations during the repair of the DNA by cell
mechanisms.
In predation, one population is the resource of the other. One can conceptualize competition as occurring horizonatally on the same resource level, while predation takes place vertically between different resource levels. Competition and predation comprise environmental pressures on the interacting populations.
When a parent cell makes several nuclei and divides to make several daughter cells, it is called Mitosis.
