How to introduce the mystery of human body?

1, the hair is elastic and can be stretched by 30%.

Hair is elastic, especially when it is wet. Healthy hair has a high level of elasticity, which makes hair styling possible and is a signal of hair health. Healthy hair can even stretch 30% because of its elasticity.

To test whether your hair has lost its elasticity, stretch it when it is wet. If a hair breaks without stretching, it may need more water. If you stretch a little and then return to the natural state, it means that the elasticity is normal. If you stretch more than usual and then break, or feel soft between your fingers, you need protein. It is very important to keep the balance between hair moisture and protein, and the best way is to do protein care.

97% people in the world have black hair.

Although most people in the world have dark hair, the color distribution of hair largely depends on the source of people. Many people may not know that even among Europeans, very light blond hair is not common. It is said that only 1% of people in this world have red hair, 2% have blond hair and the rest have black hair.

Newborns may not cry in the first few months.

In most cases, the lacrimal gland is still developing after the baby is born, so it is normal for the newborn not to cry in the first few months. Most babies start crying around 2 weeks, but some may take longer. Usually, it takes two months.

The eyes see the upside-down world, while the brain flips for us.

The image we see is made up of the light reflected by the object we see. Light enters the eyes through the cornea, which is like a window in front of the eyes. The amount of light entering the eye is controlled by the pupil, which is surrounded by the iris, which is the color part of the eye. However, because the front part of the eye is curved, the light will bend, resulting in an upside-down image on the retina. But the brain will eventually rotate the image upwards in the right way and turn it into a coherent, face-up image.

5. The nose produces 1.5 liters of mucus every day.

Mucus is a sticky gelatinous substance distributed in your lungs, throat, mouth, nose and sinuses. It is produced by mucous membranes of the nasal cavity and sinuses.

Your body is always producing mucus, but when it changes due to respiratory infection (such as flu), common cold, sinus infection or allergy, you may notice the most mucus. Normally, you produce 1.5 liters of mucus every day, but most of it flows into your throat.