Final answer:
Animals use oxygen to convert biomass into energy through cellular respiration. Plants produce glucose through photosynthesis, and animals then consume this glucose and use it in cellular respiration to produce energy. The correct answer is (d) oxygen.
Step-by-step explanation:
Animals use oxygen to change what they eat (biomass) into energy, through a process known as cellular respiration. During cellular respiration, animals convert glucose and oxygen into energy, water, and carbon dioxide. Glucose is a type of sugar that animals obtain from eating plants or other organisms that have eaten plants, and it is originally produced by plants through another process known as photosynthesis. In photosynthesis, plants use energy from sunlight to make sugars and other organic molecules. The correct answer to the question is (d) oxygen. While plants absorb energy from sunlight and convert it into chemical energy through photosynthesis, animals, including humans, are not able to perform photosynthesis but instead rely on the organic molecules produced by plants, which they acquire through their diet and break down via cellular respiration.