In the secondary structure of roots, xylem rays and phloem rays belong to ( ).
A: Secondary rays
B: Vascular rays
C: Pith rays
A: Secondary rays
B: Vascular rays
C: Pith rays
举一反三
- 以下属于直接电离辐射的是（） A: X-rays B: γ-rays C: β-rays D: neutrons
- The anti-UV mutation of microorganisms must be induced by ultraviolet rays
- Ultraviolet rays from the Sun can cause which of the following?
- X-rays and gamma rays can be used to detect and treat cancer ______.
- The anti-UV mutation of microorganisms must be induced by ultraviolet rays A: 正确 B: 错误