What are the "100,000 Why" reading cards?

The "100,000 Why" reading card is as follows:

1. Why do chickens eat sand?

Chicken's food is mainly rice and wheat, but it has no teeth and can't chew these foods, so they need sand to help grind the food. In addition, the chicken's stomach can store sand and stones, which is the way it uses sand to help digest food.

2. Why don't homing pigeons get lost?

Pigeons have very good eyesight and memory, and there is a magnet on their heads to guide them. In addition, it can adjust the flight direction according to the positions of the sun, stars and moon. With this special skill, homing pigeons can complete the task of delivering letters.

3. Why do dogs always stick out their tongues in summer?

To dissipate heat. Dog sweat glands grow on the tongue, so when the weather is hot, in order to dissipate heat, the dog will stick out its tongue to let sweat out and take away the heat.

4. What's the difference between a kitten's beard?

The kitten's beard is a very standard ruler. When a mouse escapes into a rat hole, just measure it with its beard and you will know whether it can be chased into it. If the beard touches the hole wall, it means that the hole is too small to get in. If the beard doesn't touch the hole wall, it means it can go in.

5. Why can police dogs help solve crimes?

The olfactory cells on dogs' noses are particularly developed, and the mucous membrane covering them can secrete mucus to help them distinguish different smells, so their noses are particularly sensitive.

Specially trained police dogs, as long as they smell the smell left by the bad guys, can firmly remember it, and then find the target according to this smell, so as to catch the bad guys and solve the case.