As you can see, both the aquatic plants (submerged & floating) possess the 2A : Air sacs & Aerenchyma tissue, which you must remember for the Paper 1 & Paper 2.
Speaking of Paper 2, we shall discuss on how to get perfect answers for the essay questions, such as below:
1. Explain the adaptation of the submerged plants in order to grow in the water (4 marks)
2. Explain the adaptation of the floating plant in order to stay afloat on the water surface (4 marks) (SPM 2005)
This is an explain-type question. So, we are going to use the PEE system. Since the scores are low, we are going to use only PE (Point-Explain).
Let's go to the answer outline for question #1:
Now onward to the question #2!
You can make a table form like this (make sure the sentences are complete, without arrows (-->) like I used above :-p)
It is advisable to write in paragraph form since you can save more time to focus on the writing instead of drawing the table.
There you go, a perfect 4-marks answer. I wish you all the best in your study! :-)