As humans sometimes experience, a cold environment can result in<span> </span>shivering<span>. This is when skeletal muscles begin to shake in small movements, creating warmth by expending energy. Humans can also sweat in high temperatures. The water on the surface of the skin is able to absorb a lot of heat during evaporation, resulting in cooling of the body.</span>
Sponges have specialized cells and an endoskeleton, but they lack tissues and body symmetry. ... They include jellyfish and corals, both of which have radial symmetry. All cnidarians have nematocysts, and many are bioluminescent. They may exist in medusa and/or polyp form.
Answer: a tiny muscle connected to each hair follicle and the skin. When it contracts it causes the hair to stand erect, and a "goosebump" forms on the skin.
