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Multiple Choice
Where do mammals and birds obtain the energy required to generate body heat for thermoregulation?
A
From the metabolic breakdown of food molecules such as glucose and fatty acids
B
Directly from sunlight absorbed through their skin
C
By absorbing heat from the surrounding environment
D
Through photosynthesis in specialized cells
Verified step by step guidance
1
Understand the concept of thermoregulation: Mammals and birds are endothermic organisms, meaning they maintain a constant internal body temperature by generating heat internally, rather than relying on external sources.
Recall the role of metabolism: Energy required for thermoregulation comes from the metabolic breakdown of food molecules. Metabolism involves chemical reactions that convert food into usable energy, primarily in the form of ATP (adenosine triphosphate).
Identify the key molecules involved: Glucose and fatty acids are the primary food molecules broken down during cellular respiration. These molecules undergo processes such as glycolysis, the citric acid cycle, and oxidative phosphorylation to release energy.
Eliminate incorrect options: Birds and mammals do not absorb heat directly from sunlight or the environment for thermoregulation, nor do they perform photosynthesis, as they lack chloroplasts and the necessary cellular machinery.
Conclude the correct mechanism: The energy for thermoregulation is derived from the metabolic breakdown of food molecules, which is a fundamental process in maintaining homeostasis in endothermic organisms.