In an ecosystem, which abiotic factor influences birds and mammals to have a larger body size in colder regions and a smaller body size in warmer regions?

The major characteristics of the vegetation of a locality are controlled by

In the oceans,the environment is perpetually dark at depths of:

What is the typical temperature range in high-altitude regions,which acts as a significant environmental factor?

Average temperature of thermal springs and deep sea hydrothermal vents exceeds (in $^{\circ} C$)

$-1^{\circ}C$ to $13^{\circ}C$ annual variations in the intensity and duration of temperature and $50$ to $250 \; cm$ annual variation in precipitation account for the formation of a major biome as: