Solution

Brown adipose cells contain a central nucleus with peripheral fat globules. It is one of two types of fat or adipose tissue found in mammals. It is especially abundant in newborns and in hibernating mammals. Its primary function is to generate body heat in animals or newborns that do not shiver. In contrast to white adipocytes, which contain a single lipid droplet, brown adipocytes contain numerous smaller droplets and a much higher number of mitochondria, which make it brown. Brown fat tissue also contains more capillaries, than white fat tissue, since it has a greater need for oxygen than most tissues.
So, the correct answer is option D.