Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 39 to 43.

One of the common ways to check if someone is sick is to feel their forehead with your hand. But why do we do this? What does it mean when someone's head feels hot?

The main reason why we feel someone's forehead is to check for fever. Fever is a condition where the body temperature rises above the normal range, usually as a result of an infection or inflammation. Fever is a sign that the body is fighting off a sickness, such as a cold, flu, or COVID-19. When we have a fever, our body tries to cool itself down by increasing blood flow to the skin, especially the head. This makes the skin feel warm or hot to the touch. The forehead is an easy and accessible part of the body to measure temperature, since it has a lot of blood vessels close to the surface.

However, feeling someone's forehead is not a very accurate way to tell if they have a fever. Different factors can affect how hot or cold someone's skin feels, such as room temperature, humidity, sweat, or clothing. Also, some people may have a higher or lower normal body temperature than others. Therefore, it is better to use a thermometer to measure someone's temperature if you suspect they have a fever. A thermometer can give you a more precise and reliable reading of their core body temperature, which reflects their true health status.

Feeling someone's forehead is an old-fashioned and intuitive method of checking for fever, but it is not very scientific or reliable. It can give you a rough idea of whether someone is sick or not, but it cannot tell you how serious their condition is or what kind of illness they have.

Rewrite these sentences without changing their meanings.