There exist some plants C can catch and eat insects!

The sentence structure requires a conjunction or relative pronoun to connect 'plants' with the ability to catch insects. The options are 'that', 'who', and 'than'. 'That' is a suitable relative pronoun for referring to things (plants).

1. Determine the grammatical role: relative pronoun for 'plants'.

2. Evaluate the options: 'that' (things/people), 'who' (people), 'than' (comparison).

3. Select the appropriate relative pronoun: 'that'.

that