The answer is A as during anaerobic respiration, as there is no oxygen, glucose is converted into ethanol and lactic acid to produce some energy.
Virus is non living, but once it gets a host (something to live on), it is a living being.
Over time, those who cannot live through the temperature differences/have undesirable qualities will die off. Overtime, those with desirable qualities are left and they will continue the population.
Vitamins help them function as fats.
