Structural organisation in animals
Why option A????
Poikilotherm definition is - an organism (such as a frog) with a variable body temperature that tends to fluctuate with change in environmental temperature.
Aestivation is the sleep of summer season whereas; hibernation is the sleep of winter season when cold-blooded animals faces decreased body temperatures. The duration of the aestivation is short whereas, during hibernation animal undergo longer periods of sleep.