The two groups differ in the composition of the cell wall and the lipids in the cell membrane. 3. ... Organelles contribute to efficiency in eukaryotic cells because they concentrate the biochemicals needed for chemical reactions so that the reactions proceed more rapidly.
The variations might help the organism to survive if there is a change in its environment
Eg heat resistant bacteria
The variation might help the organism survive predators
Eg. Green beetles blend with green leaves thus disabling crows to spot them
:)
Anaerobic respiration can be sustained for short periods of time because you aren’t using oxygen. We need oxygen in our body to work our muscles and pump our heart.