Question

Consider following features:
(a) Organ system level of organisation
(b) Bilateral symmetry 
(c) True coelomates with segmentation of body 
Select the correct option of animal groups which possess all the above characteristics.

• A. Annelida, Arthropoda and Chordata
• B. Annelida, Arthropoda and Mollusca
• C. Arthropoda, Mollusca and Chordata
• D. Annelida, Mollusca and Chordata

Answer 1

The Correct Option is A

The question requires identifying animal groups that possess the following characteristics:

1. Organ system level of organisation
2. Bilateral symmetry
3. True coelomates with segmentation of body

Let's analyze each characteristic and decide which groups meet all of these criteria:

1. Organ system level of organisation: This is found in more complex animals such as annelids, arthropods, molluscs, and chordates. All these groups have specialized organs grouped into systems for various functions.
2. Bilateral symmetry: This feature implies that each organism can be divided into two equal halves along one plane. Annelida, Arthropoda, Mollusca, and Chordata display bilateral symmetry.
3. True coelomates with segmentation of body:
   • Annelida: Possess a true coelom (body cavity) and segmented body structure.
   • Arthropoda: Also have a true coelom, and are known for their segmented bodies (exoskeleton partitions).
   • Chordata: Feature a true coelom and some, like vertebrates, show segmentation.
   • Mollusca: Although they have a true coelom, molluscs do not exhibit segmentation.

Based on the analysis above, the groups that possess all the specified characteristics are Annelida, Arthropoda, and Chordata.

Thus, the correct option is: Annelida, Arthropoda and Chordata. The option Annelida, Arthropoda and Mollusca is incorrect due to the lack of segmentation in Mollusca.