Answer:
The body and mind require energy to function correctly. Doing physical or mental work requires energy, which is obtained from our food. When we perform various physical and mental activities, we use up our energy reserves.
During physical activity, our muscles contract and relax, which consumes energy. If the activity is prolonged, the muscles can become tired and sore. This happens because the energy reserves are depleted, and the muscles must work harder to continue performing.
Similarly, mental activities such as studying, reading, and problem-solving require the brain to use energy. The brain consumes glucose, which is the body's primary energy source. When we engage in mental activities for an extended period, the glucose level in the blood decreases, causing mental fatigue and exhaustion.
Therefore, physical and mental activities require energy, and the body becomes tired after performing them for an extended period. This is a natural body response, and it is essential to take breaks and rest to replenish the energy reserves.
Step-by-step explanation: