Question

The body plan in which the alimentary canal has a single opening is known as ..............

• A. Cell aggregate body plan
• B. Blind sac body plan
• C. Tube within tube plan
• D. All of the above

Answer 1

The correct option is B Blind sac body plan

There are 3 types of animal body plans. These are cell aggregate body plan, blind sac body plan and tube within tube plan.

In cell aggregate body plan, the body consists of a cluster of cells which are not organized into tissues or organs. It is found in sponges.

In blind sac plan, the body has a single cavity which functions as digestive tract and coelom. The alimentary canal has a single opening. The single opening functions as both mouth for ingestion and anus for egestion. It shows tissue grade body organisation. The cells are organised into tissues. It is found in coelenterates.

In tube within a tube body plan, the digestive tract is a continuous and has two opening, a mouth for ingestion and anus for egestion. The digestive canal is present inside the body cavity and hence, this body plan is termed as the tube within a tube. It is found in the earthworm.

So, the correct answer is 'Blind sac body plan.'