Answer: billions of types of proteins
Atoms. Every element is made of a specific type of atoms.
<u>Answer</u>: an all or none response
According to the all-or-none law, it a certain threshol is crossed by a stimulus' strenght, it will cause a response in the nerve cell or muscle fiber. However, the strenght of the response will always be the same and will not vary with different stimulus strengths. The only requirement is for the threshold to be crossed.
Answer:
To reduce water loss.
Explanation:
Keeping the stomata closed during the day, helps reduce water loss when dry, hot wind blows across it.