The answer is guard cells.
Guard cells are cells surrounding each stoma. They help regulate the rate of transpiration by opening and closing the stomata. They are specialized cells in the epidermis of leaves, stems and other organs that are used to control gas exchange. They are produced in pairs with a gap between them that forms a stomatal pore (stoma).
The correct answer is B. Oxygen.
Oxygen, as a part of the atmosphere, also participates in UV protection, besides being necessary for breathing.
It's called chemical reaction.
(I'm not real sure)
Answer:
The larger the amplitude of the waves, the louder the sound. The faster the vibrations, the higher the pitch (frequency) of the sound.
Explanation:
