<span>a. Fish have a single central heart; earthworms have several hearts.
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Multi cellular organisms are made up of billions of cells each specialized to a unique role and these cells are organized into structural and functional units such as tissues and organs.
For each cell and organ to function optimally, it requires oxygen and nutrients and needs carbon dioxide and metabolic waste taken away in a continuous, never ending process.
<span>A mechanism is needed to accomplish the important function of transporting the relevant materials to and from the cell. The circulatory system fits this bill splendidly. It is a specialized organ system which allows blood and lymph to flow through the entire body carrying nutrients such as glucose, amino acids and electrolytes as well as oxygen to each cell, at the same time carting away carbon dioxide and all sorts of metabolic waste over to excretory organs to be expelled from the body.
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Jobs. Like a snow blowing company. They would not have that in Puerto Rico. But Canada might. Because they have a different enviornment.
I think it is a sex cell (not sure)
Answer: <span>95 to 133 bpm</span>
The equation for maximum heart rate would be:
max HR= 220- age
max HR= 220-30= 190
The equation to find the target for heart beat in medium intensity exercise would be:
target HR= max HR * 50-70%= 190 * 50-70%= <span>95 to 133 bpm</span>
