Question

In which of the following types of animals would you expect the digestive system to be more complex?

• A. Those with two openings, one serving as an entrance and the other as an exit
• B. Those with a single opening for the entrance of food and exit of wastes
• C. Only those complex animals that also have a respiratory system
• D. Both (b) and (c)

Answer 1

Answer: (A)

Those with two openings, one serving as an entrance and the other as an exit

• Vertebrates have evolved more complex digestive systems to adapt to their dietary needs.
• In these animals, the digestive system has two openings, one serving(mouth) as an entrance and the other as an exit(anus).
• Hence animals having a complex digestive system have two openings, one serving as an entrance and the other as an exit.
• So, the correct answer is A.