Second, why do the seedlings of plants have two leaves?

3. Why do the roots of plants always grow downward and the stems always grow upward?

4. Why do leaves fall in autumn?

5. Why do most leaves of plants face upwards?

6. Why does cactus have thorns and no leaves?

Seven, why do you want to brush the trunk in winter?

8. Why do flowers have different colors?

9. Why not water the flowers at noon in summer?

10. Why do some flowers bloom in the morning and some at night?

XI。 Why can leeks grow back after being cut?

Why are carrots nutritious?

Thirteen, why is the melon and fruit not too sweet when it rains in summer?

14. Why don't watermelon seeds germinate in the fruit?