7) Mr. Hernandez's science class learned that green plants use sunlight, water, and carbon dioxide to make their own food and release oxygen in the process. How can the class explain how
animals complete the oxygen-carbon cycle?
O Animals take in the oxygen, but do not release gas as they use energy.
O Animals take in carbon dioxide and use it to make food.
O Animals take in oxygen and release nitrogen as waste.
O Animals take in oxygen and as they use energy, carbon dioxide is released as waste.

How will the system respond to a temperature increase?

Why is the energy that results from a roller coaster's position at the top of a hill referred to as potential energy?

Athin electrical heater is inserted between a long circular rod and a concentric tube with inner and outer radii of 20 and 40 mm. the rod (a) has a thermal conductivity of ka = 0.15 w/(m*k), while the tube (b) has a thermal conductivity of kb = 0.8 w/(m*k) and its outer surface is subjected to convection with a fluid of temperature t= -15°c and heat transfer coefficient 60 w/(m2 *k). the thermal contact resistance between the cylinder surfaces and the heater is negligible. (a) determine the electrical power per unit length of the cylinders (w/m) that is required to maintain the outer surface of cylinder b at 15°c. (b) what is the temperature at the center of cylinder a?