Which phyla have the following characteristics? (state only their names).
(a) Body segmented and jointed legs, with compound eyes.
(b) Body unicellular and microscopic.
( c) Body having calcareous shell and ventral foot.
(d) Spiny skinned organisms.

Explanation

To answer the question regarding which phyla correspond to the given characteristics, we can break it down step by step:

### Step-by-Step Solution:

1. **Characteristic (a)**: Body segmented and jointed legs, with compound eyes.
- **Phylum**: **Arthropoda**
- Explanation: Arthropoda is characterized by segmented bodies, jointed appendages (legs), and often have compound eyes. This phylum includes insects, arachnids, and crustaceans.

...