<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 difference between active and passive cellular transport is that active transport requires energy for the ions and molecules to move across the cell membrane whereas passive cellular transport does not an energy input.
Answer
Macromolecules in human body
The macromolecules found in human body are:
1. Carbohydrate,
2. Proteins
3. Lipids, and
4. Nucleic acids.
Elements they common share
All these macromolecules have three elements in common which are:
1. Carbon
2. Hydrogen, and
3. Oxygen.
These elements constitute about 95% of human body.
Difference in Chemical properties
Carbohydrate is composed of glucose monomers, which may have aldehyde functional group or ketone functional group. Protein is composed of monomers called amino acids. Each amino acid has carboxylic functional group, amino group, alkyl or aryl group and hydrogen atom. Lipid is composed of fatty acids and glycerol. While nucleic acid is composed of monomer called nucleotide. Each nucleotide is composed of pentose sugar, phosphate group and nitrogenous group. Due to the presence of different functional groups all these macromolecules have chemical properties different from each one
According to http://www.ucsusa.org/global_warming/science_and_impacts/science/ozone-hole-and-gw-faq.html#.WQjhDfW...
I think the answer is B.CFC
Hello! The correct answer for the question is: Burns.
I really hope this helped you! c:
