How are primary and secondary succession different?

Primary succession starts on bare rock and is on land where there was no previous growth. Secondary succession is growth on land where there has been previous growth.

Explanation:

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B. Birds allow their temperature drop in order to increase their production efficiency.

Explanation:

Most birds can drop the temperature a few centigrade degrees, while there are torpid birds capable of lowering much more. Birds can drop body temperature in response to environmental conditions. Bird species including, among others, swifts, hummingbirds and chickadees are capable of regulating body temperature during torpor state. There are different morphological and behavioral adaptative traits that enable birds to minimize the cost of thermoregulation. In the first place, epidermis surface allows heat loss to the environment, while arteries and veins in the legs help to retain heat in cold conditions.