its to do with cells and arteries
2007-01-15 09:55:56 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Biology
The clue is in "single celled". They can cope by diffusion (large surface area compared to volume)
2007-01-15 10:00:27 · answer #1 · answered by Anonymous · 1⤊ 0⤋
Think about what you're asking. Why would a single-celled organism need a transport system?
2007-01-15 10:36:53 · answer #2 · answered by sdc_99 5 · 0⤊ 0⤋
Transport In Unicellular Organisms
2017-01-11 15:50:36 · answer #3 · answered by Anonymous · 0⤊ 0⤋
This is one of those scenarios where size matters! In many unicellular organisms (specifically, bacteria), waste products, nutrients, etc. can travel through the cell or out of the cell by diffusion from one part of the cell to another. There are no boundaries between locations in the cell. And there are no cell boundaries to cross between in the same organism - the entire organism is only one cell!
In contrast, the cells of multicellular organisms are compartmentalized - they have organelles, and even organ systems. Compartments have boundaries. When you have boundaries, you need transport systems. Also, multicellular organisms are (almost always) larger than unicellular organisms - you need active transport systems to move a molecule from one part of the body to another.
2007-01-15 10:07:27 · answer #4 · answered by Notyourmother 2 · 0⤊ 0⤋
Because they don't need to send anything to any other cells. Everything is in one place so there is nowhere to send it.
2007-01-15 10:00:59 · answer #5 · answered by Anonymous · 0⤊ 0⤋