Answer: the answer is (d)
Explanation:
C. Permafrost
Permafrost is the layer beneath the "active layer". The active layer consists of soil that freezes and thaws every year. However, the requirement for permafrost is that it be frozen for two or more years consecutively. This is why permafrost exists in cold environments such as tundras.
The answer is: 'constrict the blood vessels in their large ears to reduce transfer of external heat to the blood in their ears.' This is an example of thermoregulation. Thermoregulation is the ability of the<span> </span>body to keep body temperature<span> within certain boundaries, even when the temperature of the surrounding environment is very different. The regulation of temperature by thermoregulating organisms is one aspect of </span>homeostasis. By using heat exchange systems, such as employed in this example, the animal will need to expend less energy on behavioural adaptations to maintain a constant body temperature.
If I c<span>onsider this northern site of primary succession following the retreat of a glacier, the characteristics that I would expect to see among the plant comprising the pioneer species are the processes of ecological succession and the primary succession.</span>
Peristalsis<span> is a radically symmetrical </span><span> contraction and relaxation of muscles</span><span> that propagates in a wave</span><span> down a tube, in an anterograde direction.</span>
