SA/V ratio and temperatures. :D

What causes the higher body temperature of birds?
A high metabolic rate, so, when glucose is broken down, some is converted into heat energy, which maintains heat.

What is the relationship between bodymass and time spent feeding?
The greater the amount of time spent feeding, the lower the body mass, as, as the body mass increases the surface area to volume ratio decreases, therefore, there is less surface area to unit of body volume to loose heat through, so the rate of heat loss is slower, and hterefore, less energy is needed to maintain body temperatures (and also, food.)

Low raio of SA/V helps maintain a body temperature:
Large volume mean there are lots of cells repiring and producing heat energy. Also, surface area is relative to volume, and if it is very small there is less for heat to escape from, so rate of heat loss is slower.

How does the given trend: 'The greater body mass and length, relies on a higher latitude, and lower winter temperature', explain how possums adapt to where they live:
An increase in size means a reduction in SA/V ratio, meaning the area through which heat can be lost can be reduced, compared with the size of the posum. The conserves heat, and lowers the amount of energy required to maintain body temperature.

Suggest a reason for no adaptation in size in cooler climates:
SA/V is only one thing that can be adapted, other things like insulating fur can make a difference. As can higher metabolic rates, as more energy could be generated to compesate for heat loss. There are also behavioural habits like migrating and hibernating that could affect it.

(: That's alllll... :D