What are the answers to the following biology questions about animal body plans and classification?

Here are the answers for Activity 1:

1. An arrangement of body structures in relation to some axis of the body: Symmetry
2. An evolutionary trend in the animal kingdom toward centralisation of neural and sensory organs in the anterior region of the body: Cephalization
3. Triploblastic animals that lack a through-gut and coelom: Acoelomates
4. Animals with two cell layers: Diploblastic
5. A collective name for animals without a backbone: Invertebrates

Here are the answers for Activity 2:

2.1 Phylum containing organisms that are triploblastic: BOTH A AND B (Platyhelminthes and Annelida are both triploblastic)

2.2 Animals without back bones: A ONLY (Invertebrates are animals without backbones)

2.3 A fluid-filled body cavity lined by mesoderm: B ONLY (A coelom is a fluid-filled body cavity lined by mesoderm)