Ans 3:
Class : Class 9 
                                                                                                        
                                                                                                        Because of "in the water " the correct answer will beI also agree that the question is wrong because the answer will be 'aquatic plants'.
                                                                                                    
                                                                                                    Ans 5:
Ans 11:
Class : Class 5 
                                                                                                        
                                                                                                        I also think it is wrong because 'underwater plants' and 'fixed aquatic plants' also live in water.
                                                                                                    
                                                                                                    Ans 12:
Class : Class 8 
                                                                                                        
                                                                                                        HELLO,IN THE MASTER ANWSER IT IS WRITTEN TAHT PLEASE CHECK THE THIS QUESTION FROM THE REVISED EDITION OF GK BOOK.-KINDLY TELL THE CORRECT ANS. OTHERWISE I THINK THAT THE CORRECT  ANS SHOULD BE ABEACAUSE IT IS WRRITEN IN THE WATER OR AQATIC PLANTS. THANKYOU
                                                                                                    
                                                                                                    Ans 13:
Class : Class 8 
                                                                                                        
                                                                                                        It is supposed to be A despite them both being aquatic plants. The reason is because it wrote 'in the water' not 'on the water'