Which of the following statements is/are incorrect? a. Cactus has spines on its stems to store water. b. Sweating does not occur in a camel. c. Frogs breathe through moist skin and lungs.

This is incorrect. Adult frogs breathe through their lungs and exchange gases through their skin, and the lining of their mouths. This option is correct because all the statements are incorrect. Cactus have spines on stems as modified leaves. The fleshy stems of cactus are for storing water. Sweating does occur in a camel, although it is very less and in very hot conditions. Adult frogs breathe through their lungs and exchange gases through their skin, and the lining of their mouths.