The correct answer is option C. You feel hungry.
C. You feel hungry is a sign that your cells need more energy. Hunger is a physiological response that signals a deficiency in nutrients and energy required for cellular activities. When the body's energy reserves, particularly glucose levels, drop, it triggers the release of hormones such as ghrelin and signals the hypothalamus in the brain. This initiates the sensation of hunger, prompting the individual to consume food and replenish energy stores.
During the process of digestion, the body breaks down food into essential nutrients, including carbohydrates, proteins, and fats, which are then converted into energy through cellular respiration. The intake of food helps maintain adequate energy levels for cellular functions, growth, and maintenance.
Option A, an increase in breathing rate, is often associated with the body's attempt to meet increased oxygen demand during physical activities, but it doesn't directly indicate a need for more energy. Options B and D, shivering and feeling thirsty, are responses related to temperature regulation and fluid balance, respectively, rather than direct signals of the need for increased energy.
Therefore, the correct answer is option C. You feel hungry.