Atmosphere refers to the thin blanket of air that surrounds the earth.
It serves many important functions such as:
It contains a mixture of gases that are essential for the existence of life on earth. For example, carbon dioxide is essential for photosynthesis and oxygen is essential for cellular respiration.
It also serves as the reservoir of water in the form of water vapor. Thus, it forms an important constituent for the water cycle.
It maintains the temperature of the earth. Through the greenhouse effect, it maintains the temperature of the earth in limited ranges.
It protects the earth from harmful rays of the sun. For example, ozone inhibits the entry of most of the UV rays of the sun into the earth environment.
Cells have many structures inside of them called organelles. These organelles are like the organs in a human and they help the cell stay alive. Each organelle has it's own specific function to help the cell survive. The nucleus of a eukaryotic cell directs the cell's activities and stores DNA.
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.
