Which adaptation is used by polar bears to maintain internal homeostasis in cold temperatures?
three layers of fur
blubber
finding shade underground
white skin

The right option is; blubber

Blubber is the adaptation used by polar bears to maintain internal homeostasis in cold temperatures.

Blubber is the thick layer of fat located below the skin of polar bears. Blubber is about 10cm (4 inches) thick. Blubber is mainly used for insulation. It helps polar bears to maintain internal homeostasis in cold temperatures. Blubber also serve other functions such as helping the polar bears to float naturally when swimming in water, and it is also used for storing food in case there is limited food supply such as during summer.

fertilization, pictured in figure 24.23a is the process in which gametes (an egg and sperm) fuse to form a zygote. the egg and sperm each contain one set of chromosomes. to ensure that the offspring has only one complete diploid set of chromosomes, only one sperm must fuse with one egg. in mammals, the egg is protected by a layer of extracellular matrix consisting mainly of glycoproteins called the zona pellucida. when a sperm binds to the zona pellucida, a series of biochemical events, called the acrosomal reactions, take place. in placental mammals, the acrosome contains digestive enzymes that initiate the degradation of the glycoprotein matrix protecting the egg and allowing the sperm plasma membrane to fuse with the egg plasma membrane, as illustrated in figure 24.23b. the fusion of these two membranes creates an opening through which the sperm nucleus is transferred into the ovum. the nuclear membranes of the egg and sperm break down and the two haploid genomes condense to form a diploid genome.

explanation: