Like D. Codon is the answer
Placenta
It also does not allow the maternal and fetal bloodstreams to mix
As the bear enters hibernation, its metabolic processes such as body temperature, heart rate, and respiratory rate are reduced. But bears do not lower the body temperature as much as once thought. Their hibernation temperature is around 88 degrees and waking temperature is 100 degrees F. This relatively high sleeping temperature allows bears to become fully alert if aroused, perhaps to enable the bear to protect itself from predators and other dangers without unnecessarily taxing their energy reserves. Over the course of a hibernating season it is thought that bears use approximately 4 thousand calories a day, which results in a weight loss of about 20 percent of it body weight by spring.
Explanation:
an individual animal, plant, or single-celled life form.
