A closed system is a system that makes no physical or chemical exchanges with its environment. Of these systems provided as choices (tree, human, clock, car), only a clock does not make exchanges with the environment, except for energy.
Therefore, of that list, only a clock would be a closed system.
Hope that helped! =)
Answer is B
a eukaryote is any cell that contains a nucleus
A chromosome consists of a single, double-stranded DNA molecule. Chromatids are two molecules of double-stranded DNA joined together in the center by a centromere. Chromosomes have a thin ribbon-like structure. Chromatids have a thin and long fibrous structure.
Answer:
d. dilation of the blood vessels serving the skin and digestive viscera.
Explanation:
Cardiovascular effects of the sympathetic division include all of the following EXCEPT dilation of the blood vessels serving the skin and digestive viscera.
