<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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The answer is rain percolates through the pavement into the ground below, causing cracks in the pavemen
Answer: D
Explanation:
Seasons are not biotic bc they are not living, and we know from playing Minecraft that savannas are not covered in conifers but are covered in grass and a few trees
*Beep Beep*
Lettuce
A) the ozone layer, it is the one that takes the uv light from the sun
