What is the difference between a negative feedback system and a positive feedback system?
(a)- in a negative feedback system, the control center raises or lowers the set point until the signals from the sensor stop; in a positive feedback system, the set point remains constant.
(b)- in a negative feedback system, the organism is most likely experiencing a disease state. in a positive feedback system, the organism is most likely healthy.
(c)- in a negative feedback system, the consequences of the action can harm the animal; in a positive feedback system, the animal is not harmed.
(d)-in a negative feedback system, the control center signals the effector to go "on and off" to maintain a steady state (or stable equilibrium); in a positiv

Clothing made of several thin layers of fabric with trapped air in between, often called ski clothing, is commonly used in cold climates because it is light, fashionable, and a very effective thermal insulator. so it is no surprise that such clothing has largely replaced thickand heavy old-fashioned coats. (a) consider a jacket made of five layers of 0.1-mm-thick synthetic fabric (k = 0.13 w/m·°c) with 1.5-mm-thick air space (k = 0.026 w/m·°c) between the layers. assuming the inner surface temperature of the jacket to be 28°c and the surface area to be 1.25 m2, determine the rate of heat loss through the jacket when the temperature of the outdoors is 0°c and the heat transfer coefficient at the outer surface is 25 w/m2·°c. (b) what would your response be if the jacket is made of a single layer of 0.5-mm-thick synthetic fabric? what should be the thickness of a wool fabric (k = 0.035 w/m·°c) if the person is to achieve the same level of thermal comfort wearing a thick wool coat instead of a five-layer ski jacket?