Question

'X' is a phylum which has organisms with jointed appendages, and a segmented body.
'Y' is a phylum which has organisms with a notochord present at some stages of their life.
Identify 'X' and 'Y'.

• A. X- Nematoda Y- Protochordata
• B. X- Molluscs Y- Protochordata
• C. X- Arthropoda Y- Nematoda
• D. X- Arthropoda Y- Protochordata

Answer 1

The correct option is D X- Arthropoda Y- Protochordata

Arthropod means jointed legs. Animals which have jointed appendages belong to this phylum. This is the largest phylum in the animal kingdom. Features of Arthropoda are:

1. They are bilaterally symmetrical.
2. They have jointed appendages and a segmented body.
3. They have a well-differentiated organ and organ system.
4. They have an open circulatory system, but they do not have differentiated blood vessels.

Protochordates have the following features:

1. They are bilaterally symmetrical and triploblastic.
2. They have true coelom.
3. They are found in marine habitats.
4. Notochord is present at some stages of their lives.