Final answer:
A contractile vacuole's primary function is expelling excess water and waste from the cell through exocytosis. It does not store food or detect light; thus, the correct answer is (d) 'None of the above'.
Step-by-step explanation:
A contractile vacuole is an organelle found in some unicellular eukaryotic organisms, such as amoebae and paramecia. Its primary function is to excrete excess water and waste from the cell, ensuring the organism does not burst in a hypotonic environment. This process is known as exocytosis, where the contractile vacuole merges with the cell membrane to expel wastes.
Therefore, the correct answer to the question 'A Contractile Vacuole _____' is: 'Expels water'. Option (b) 'Expels water, stores food' is incorrect because the contractile vacuole does not store food; that function is reserved for different types of vacuoles. Also, contractile vacuoles do not detect light. Hence, the best answer from the given options would be (d) 'None of the above' since none of the pairs correctly describes the function of a contractile vacuole.