Researchers at Cornell University have demonstrated that homing pigeons can sense changes in the earth's magnetic field, see light waves that people cannot see, detect low-frequency sounds from miles away, sense changes in air pressure, and can identify familiar odors.

The question asks for a grammatically correct and parallel construction. The original sentence uses 'can sense' and 'can identify' - repeating 'can' is unnecessary and disrupts parallel structure. Option C correctly places both verbs in their base form ('sense' and 'identify') after the implied 'can', creating proper parallel structure: 'can sense changes...and identify familiar odors.' The other options either maintain the unnecessary repetition of 'can' or use awkward passive voice constructions.