All animals with bilateral symmetry have __________ germ layer(s).

• A. zero
• B. one
• C. two
• D. four
• E. three

Answer: (E)

Verified step by step guidance

1. Understand the concept of germ layers: Germ layers are the primary layers of cells that form during embryonic development in animals. These layers give rise to all tissues and organs in the body.
2. Recognize the types of symmetry in animals: Bilateral symmetry means the body can be divided into two identical halves along a single plane. Animals with bilateral symmetry are more complex than those with radial symmetry.
3. Identify the germ layers: In animals, the three primary germ layers are the ectoderm, mesoderm, and endoderm. These layers are present in animals with bilateral symmetry.
4. Connect bilateral symmetry with germ layers: Animals with bilateral symmetry typically have three germ layers, which are essential for forming complex structures and systems.
5. Conclude that animals with bilateral symmetry have three germ layers: ectoderm, mesoderm, and endoderm, which contribute to their complex body structures.