its the circulatory system
Chromosomes are lined up in the middle of the cell during metaphase.
Answer:is a transfomation of a per existing rock
Explanation :Marble ,Slate.
<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.