Answer:
Winter,to conserve heat in the body.
Explanation:
The adaptation of the phospholipd bilayer ensures that the phospholipid tails face one another inwards,while the hydrophilic polar head point outwards.These tails can either by saturated or unsaturated. The high the number unsaturated chains the more the fluidity of the cell membrane,This because the un saturated chain are usually bent -kink-and therefore affects the alignments of the chains make them not properly arranged giving room for fluidity(heat).
In addition the longer the length of these chains the higher the fluidity of the membrane.
Note the more saturated the chains ,the more packed the cell membrane the less fluidity and tendency to freeze up.
In cold environment,as the temperature drops,membrane becomes less fluid, bacteria could not control body temperature,and the membrane fluidity drops.To survive these bacteria responds by increasing the number of unsaturated fatty acids chains(desaturated ) to increase the fluidly to keep warm to avoid been frozen up,thus winter is the beneficial
Haploid cells! Hope this helps :)
Mutations result from an error in DNA replication, should it be from an alien source (like radiation) or simply a mistake in replication.
Migration of organisms to a new population would alter the DNA by adding new genes, but it would not mutate them.
They both involve sell and reproduction.