Suppose the average daily metabolic rate for certain types of animals can be expressed as a function of mass by r= 145.1m , where m is the mass of the animal (in kilograms) and r is the metabolic rate (in kcal per day). dm a. If the mass of an animal is changing at a rate of -, find dr dr b. Determine - for a 120-kg animal that is gaining mass at a rate of 4 kg per day. dm dr a. If the mass of an animal is changing at a rate of , find dr dt