The right answer is <span>A) semi-permeable membrane
<span>A semi-permeable membrane is a membrane permeable to a liquid (solvent) and impermeable (or poorly permeable) to substances dissolved in the liquid (solute).
</span>The tubule of a kidney consists of a semi-permeable membrane and has also specific transporters which allow absorption and reabsorption. These "tools" allows some substances like ions to be absorbed/reabsorbed (by the transporters), without any changes in the concentration of the other substances (because both the membrane and the transporters stopped them).</span>
Answer: Density-independent factor
Explanation:
The answer is B , it's the most one that makes sense.
1. the plant produces the seed
2.pollen fertilizes the female part or the plant
3.the squirrel collects the seed
4. the squirrel buries the seed
5. squirrel doesn't come back for seed
6. a new plant grows