Experimental method: It refers to the method of simulating or interfering with the signals used between the animals that undergo behavior or the animals that accept behavior, and then analyze the main factors that stimulate behavior. Which of the following options are experimental? ['Use a camera to shoot the movement of a cheetah and study how the cheetah chases its prey.', 'Observing bird breeding activities with a telescope.', 'The zoo used CCTV to study the process of the remaining Siberian tigers.', "Dolphins are disturbed by sound waves in water, and dolphins' response to sound waves is observed."]