Knowledge Point 01: Hair Turns White Due to Decreased Melanin in the Elderly
As people age, their bodily functions decline, resulting in a reduction in melanin formation in the hair, which gradually turns white.
Detailed Explanation: The color of hair is primarily determined by melanin; the more melanin, the darker the hair. However, as people age, various bodily functions gradually decline, including the ability to form melanin.
Therefore, the melanin in the hair of elderly people gradually decreases, causing the hair color to fade and ultimately turn white. This is a manifestation of natural aging in the human body and a sign of declining bodily functions.
Knowledge Point 02: Infants Cry Loudly Upon Birth Due to Taking Their First Breath of Air
Infants cry loudly upon birth because the first breath of air they inhale strikes their vocal cords, producing a sound similar to crying, which is actually the beginning of normal breathing.
Detailed Explanation: When infants are born and leave the womb, they immediately begin to breathe the air outside. At this point, the first breath of air they inhale strikes their throat vigorously, causing the vocal cords to vibrate and produce a sound similar to crying.
This is actually the beginning of normal breathing for infants and an important sign of their adaptation to the outside environment. Therefore, infants crying loudly upon birth is not because they are unhappy but rather a manifestation of normal physiological phenomena.
Knowledge Point 03: The Two-Jointed Thumb Complements the Functions of the Other Four Fingers
The thumb has only two joints to better complement the functions of the other four fingers; three joints would make it weak, and one joint would make it impossible to grip objects freely.
Detailed Explanation: The structure of human fingers is very unique. Except for the thumb, the other four fingers have three joints each. The thumb, however, has only two joints, a design that better complements the functions of the other four fingers. If the thumb had three joints, it would be weaker and unable to effectively lift heavier objects.
And if the thumb had only one joint, it would be impossible to freely grip objects in coordination with the other four fingers. Therefore, the two-jointed design of the thumb meets the needs of human hand function, enabling us to use our hands more flexibly and effectively.
