Be alone make you go faster but be in a community make you go longer.
The answer is global warming
When energy passes from one trophic level to the next, I would guess that the two factors which decrease the total amount of energy from being passed up are:
1. An organism does not assimilate all the energy of food consumed. Within a consumer, digestion and assimilation of energy is not 100% efficient: some of the energy is lost.
2. A large proportion of energy assimilated by a producer and consumer is lost through respiration, i.e., day-to-day maintenance of metabolic processes.
I think 1 is C and 2 is A
