The correct option is A An overwhelming majority of animals and nearly all plants maintain a constant internal temperature
Warm blooded animals like birds and mammals are the only animals that can maintain a constant internal temperature, most of the animals do not regulate their internal temperature.
The largest purely terrestrial animal found in Antarctica is a flightless midge (a flightless fly) that grows no more than 13mm in length. All other Antarctic animals are either smaller than this or migrate spending some of the year away from the deep south and the extreme cold. They either swim or fly away - and back again.
An orchid growing as an epiphyte on a mango branch is an example of commensalism, because the orchid derives its nourishment from the mango tree, but the mango tree however is not harmed.