Help with Biology homework?

Question

These are the ones I can't figure out.

1.Unicellular frechwater organisms are constantly surrounded by water. How do they compensate for osmosis and stay alive?
2. Plant roots or other structures may be surroinded by water. How do they compensate for osmosis and stay alive?
3. Give an exaple of a cell type that cannot compensate for osmosis. Explain what happens to them.
4. Sea water has a higher concentration of solutes than do human cells. Why might drinking large amounts of sea water be dangerous for humans?

Help?

Answer 1

1. Unicellular organisms have a contractile mechanism to expel water.

2. Plant roots have rigid cell walls and they actively transport water to the stem and leaves.

3. Red blood cells will burst in water.

4. Humans have no mechanism to excrete sodium. In fact the human body try to reabsorbed all the sodium from the urine.

Answer 2

1. Bulk water export.
2. Cell walls.
3. RBCs. (Don't have mitochondria or nuclei)
4. There's some fancy things that happen, but just think simply about what happens when you eat chips.

Hopefully you can explain them yourself? Good luck!